Dual citizenship renunciation & name change

[veryconcerned]

I'm a naturalised British citizen with a dual citizenship (British/Russian). I have a corresponding remark in my British passport, presumably because the original passport has a patronymic in it that is not in the British passport.

I am currently going through the process of renouncing my Russian citizenship (for several reasons). When I finish the renunciation (which apparently will take up to five more months), I will get a certificate in Russian stating that I'm no longer a Russian citizen.

I also want to change my name. Normally, dual citizens are required to change their names in their non-British passports first, but it is likely impossible in my case. Thus, I'm hoping to only need to process the change with the UK government after the renunciation process is complete.

How should I proceed after that? Theoretically, I can just do a deed poll, but then my naturalisation certificate will be wrong, my passport's "observations" will be incorrect (since I'll no longer hold a Russian passport), and I'm not sure how HM PO will look at the deed poll since in their records I'll still be a dual citizen.

Should I translate the renunciation certificate (myself? via some sort of notary? does it need to be legalised?) and send it to HM PO together with the deed poll? Will they replace my passport in the new name and without the official observation of me holding a Russian passport?

Should I amend my naturalisation certificate, and if so, how?

Also, should I even wait till the renunciation is complete (which apparently will take up to five more months) before I do the deed poll and update my banks/driving licence/electoral roll?

Any other advice?