I doubt HMRC are interested in your address beyond having somewhere to send correspondence to - I'd just put your home one down, tbh.
As everyone has said (and this comes up time and time again) you DO NOT have to register as a prostitute, or 'escort', or whatever, in order to claim for condoms - whilst it wouldn't be helpful to put yourself down as a window cleaner, an essentially meaningless term like 'therapist' or 'entertainer' is fine. They don't care what you're doing, they just want you to pay your tax.
I would also ring them if you're not sure (or ask an accountant) but two prostitutes working from the same flat is certainly a brothel whether you're both there at once or not. HMRC are not the police though, and they aren't going to care one way or the other but if both of you register as therapists (I think 'life coach' was another that was doing the rounds a while back) it doesn't matter one way or the other .
I know most of the replies state that I shouldn't claim that I am an escort, however after reading various articles it just made the most sense that I should declare escort. I.e for peace of mind being one reason. The other reason I have been looking at allowable expenses & don't really see how these tie with with being a therapist or whatever since you have to keep receipts etc to prove your allowances?
Another issue is neither me or my friend are claiming that it is a businesss address due to
Lack of knowledge on the subject, more than anything.
I guess that I assumed because technically it is an "illegal" set up because there are 2 of us that it would break confidentialality between hm, police and landlord. I thought I would find out on here with someone else in the same situation Before ringing hm themselves.
I wish I could work at home but I have a toddler & a partner so that idea does not work unfortunately.