Gotten myself in a muddle

Hi there -

I am a young professional and moving around in London, a LOT, and so I have kept my mother's address for most of my bank accounts [debit and credit] and other things. I also legally own a percentage of the address my mother lives in due to a death in the family, so assumed it would be fine to use this as my bank address.

I checked my credit score with credit monitor a few weeks ago, and it was good, and said that I was registered to vote and had been registered at the same address for a long time (I assumed this must be my mum's).

This reminded me that I should probably check that I am indeed registered and I have a postal vote, but the only way I could seemingly do this was by registering to vote on the gov website, which I did and completed the postal vote forms sent to me by the local council (local to my mum's address).

My mum has just text saying that she has a letter for me from the electoral roll (presumably confirmation of my postal vote), but that if I register to vote at her house, she wouldn't be entitled to the 25% council tax discount she gets for living alone.

I obviously thought that I was registered there anyway, having never removed myself from that list, but my mum says that she wouldn't have put me on any of the electoral canvass forms they send around the last few years (so maybe that would have taken me off?)

I was then confused with why my credit report would say that I was registered, in the same place for a long time, if I wasn't - so I went and checked the full report on the app and the homepage still says 'registered to vote', but the more detailed personal information tab says 'electoral roll information' indeed with my mums address, but dates from 2010 - 2016.

I am now wildly confused: my credit score said I was registered, but then kind of suggested I wasn't. Now I have re-registered, can I undo it so that my mum doesn't lose her single person discount? And if I now undo it, since all my credit cards etc. are registered at that address, will it now have a negative effect on my credit score?

Obviously, I'm not very well read up on the electoral roll/credit score/council tax interdependencies and now worry that I have made some silly mistakes here, hoping I can fix them without causing any problems for my mum.