Name change

I'm a dual US/UK citizen and recently legally changed my name in the US. I plan to also update my name in the UK to this name. Ideally I would get the name change enrolled but the process seems arduous at best. Given that I can update the name on all of my major documents/accounts (e.g. passport, driving license, bank accounts, etc) with an unenrolled deed poll, I will probably just do this for now. My questions:

1) Which if any deed poll service is recommended, taking into account factors such as document validity (e.g. acceptability to various institutions), process difficulty, cost, time, etc?

2) Which major entities if any only accept an enrolled deed poll? e.g. parents' wills, particular financial institutions, etc?

3) Just curious: is there any issue if my name has been legally changed in the US but I continue using my old name in the UK until it is legally changed by deed poll?

The name change is a minor alteration to my surname.