becoming a Ms... who to tell /inform???

I think that's the nice easy option and you don't need to advise any change. When people address you as miss just advise them it's ms and ask them to amend their records. If you have anything where someone us named as next of kin advise them this is now your husband but you are keeping the same name. As far as I'm aware wills are invalidated by marriage unless they say different so if you have a will you probably need a new one. It may be worth ringing the tax office, bank and any life insurance etc you have to double check but I'm pretty sure you won't have to do anything after all there is no legal requirement for a woman changing from miss to Mrs.

Yes it's a doddle.
I'm a Ms. You just ask the various places that address you with a prefix to change it, there's no need to prove anything.

I kept my surname but changed my title. Some places just changed it for me when I asked, some wanted a copy of my marriage certificate. Just ask and see what they say.

Fab!

Thanks ladies. ..knew I could rely on you xxx

Oops, I didn't bother phoning the tax/ pension people or anyone else! For most things I was Ms before I married anyway. Part of the reason I kept my name was to avoid admin.