Abrahamicstyle magick is not my particular field of study but perhaps this might be helpful.
Banishing is pretty much forcefully expelling negative energy and entities from your working space. I would think that it would create some repercussion in the spiritual realm after something is rather rudely ejected from its seat. We all create our sacred spaces but sometimes we neglect to investigate them beforehand to see if it might have belonged to something else.
For a person that has a more light approach to their magick, instead of forcefully banishing, one could take a bit of extra time to permit a more polite way of clearing a space. Something more along the lines of giving energy permission to go about its journey and leave your intended work area before more forceful means are initiated. I have found this to be a better way in my form for sitting out or astral travel. I find my presence in the realms is much more non confrontational. One catches more bees with sugar than with vinegar. I imagine it will also relieve those instances of flashes from energies that haunt you later. Hopefully,others here might share an idea that matches your path more specifically.
You cant. The ritual was designed to develop those senses.
As for the LBRP forcefully getting rid of spirits, it doesnt really. It can be modified for that use, but generally it cleanses the Self. The beings it does get rid of are not really beings at all, they are like energies which are semi-autonomous. The LBRP acts on the lowest astral plane, higher beings are generally not effected.
Of course that is my opinion and a decades worth of experience, others disagree. I think intent when using the ritual has a major role to play.
What did you want this ritual to do for you? There might be something else you can do which does not involve working with the astral and spirits.
Practicing any type of magic, ideally requires you to let go of your Beta state of mind functioning. Mind crippled with OCD and General Anxiety will refuse to let go by intensifying fears and obsessive thoughts. This is very natural process for people prone to these mental states, who additionally undergo some type of trauma while practicing their craft. It takes some time for one to heal and just observe the thoughts, except them and let them go. Letting go and accepting things allows you to enter the states, which allow you to leave these behind. All this takes time and the time that it takes depends on the person.
For example, when I am doing trance work, dreaming in particular way and having near death experiences or spiritual experiences, I do not experience either intrusive thoughts or anxiety. I might experience intense fear, only if things become scary really fast, so I drop down back in my body, awake or snap out of the trance state. However, nothing heals my anxiety and mild OCD like experiencing what people call The Light. LBRP requires you to connect to the very emanations of The Light. If you need to watch one of them it is the, Elohim Yah. The path of the left hand as depicted on Kabbalistic Tree of life and associated with Gevurah (Din). This Name(Emanation) represents The judgment of the Creator and its severity and anger. This is the one that can trigger things inside some people, who harbor guilt, shame and fear of being judged. If you can manage to balance this Sepiroth with the help of Chesed and Tipheret, you should be good.
An intrusive thought should not be occurring, if you are in trance state or any other elevated state of being. Having said that some people just have so strong mind that this can occur. Your patron might only tell you techniques to go about it, but they cannot do the internal work for you. The only being that could do the internal work instead of me was The Light and only because I could connect to it prior to this happening. The beings who are part of worlds of Formation and Creation, which we call commonly angels also could assist, if you have good connection with them, but keep in mind they are extension of the Light.
One should never allow klipot and any other kind of negative beings to prevent ones soul to reach its highest potential. One should never allow their own fear, judgment and anger to consume them. When this happens, one looses their light and their connection to upper realms and worlds. Pain, hurt, shame and guilt also lock souls in perpetual realm of silence and darkness. Working on oneself and your negative emotions and thoughts is the best way to prevent them repeating again.
I agree with Hadit that this ritual mostly gets rid of beings of the lower realms. I have performed it multiple times because I work and attract with multiple types of spiritual beings. Later I have performed EVP recordings and the usual ones will be still hanging around and commenting about this amazing Light they saw (experienced it). They do not mind it as long as they do not harbor some negative and malicious nature. I have long assumed they like this Light and that is why they stay. The Light that does not depend on Light.
Any sort of occult practice or magical workings can compromise your well-being on long term if prone to this. Take a break, when you feel you need one. I shut down my abilities for the most part, meditate, do my grounding and gardening and heal. When I feel that I have recovered and ready to journey again I start again. Just know thyself and follow your inner feeling.
The angels evoked clear the space because they are high vibrational entities, they are also the rulers of the terrestrial elements on the lower material plane- which means lower spirits essentially either get repelled or are put in their proper place. I consider it more a balancing rite than a banishing rite- not everything is banished, but the area becomes harmonious and therefore suitable for further working.
As for protecting from curses, it can help, but I would not rely on it exclusively.Most of the time you will find people do not curse other people, the ones that go around cursing willy nilly probably have no idea what they are doing anyway. I actually find uncrossing baths good for getting out of curses, also spells which have an element which absorbs the curse such as a black candle surrounded by salt which is burned completely and the remnants buried somewhere away from the home or thrown into a flowing river.
The fact of the matter is, the LRP works upon the plane known as Assiah- it just touches the lower astral, it's main effects are on the Etheric planes close to the Earth. Most magical actions reside above this in the plane of Yetzirah at the very least. Good magick passes through the highest plane to the lowest.
If you are interested in the Golden Dawn rituals and this ritual in particular I recommend By name and image by Peregrin Wildoak. Also the newest Golden Dawn book by the Ciceros. There is also a good section on the ritual in Regardie's Middle Pillar- which you can probably find online- just don't take the psychological language to heart.