Question Author
Thank you all for your answers! I'll explain why I asked, and maybe someone will be able to elaborate.
In Mexico, where I originally come from, you are not allowed to change your name, ever. Many married women do take their husbands' surnames, informally/socially, and of course artists and sportspeople have sort of professional names, but legally everyone keep their 'birth' names for good.
Mexican names are composed of one or two (sometimes more than two!) given names, plus the father's surname and the mother's surname. So lets say that my full name is Banana Orange Mango Apple. I came to the UK some time ago, and later married a British citizen. I thought it would be practical to use a 'British name' here, but didn't want to change my signature because I would have had to change it in Mexico too (there, as I believe is the case in most Western systems, how signatures look is entirely up to each individual but you do need to go through a complicated process in order to get a change recognised) or have two different signatures, which would be impractical (probaly illegal??) and very stressful: I know I would forget which one I was suppoed to use at the most inconvenient moment!
Anyway, my signature reads 'Orange Mango A.', and because my husband's surname is Apricot, the A is very useful.
So different name, same signature. I explained this to banks, utility companies, my employer, etc. and nobody has had a problem. Now that most cards are chip and pin, this is even less likely to be a problem, but the other day I used my only non-chip and pin card and the nosy till attendant said that all signatures must match names, and was really annoying, even though she had already validated the transaction. So I thought I'd better check on the internet, but didn't find much. However, my searches did bring me here, which is great!