I didn't tell my bank, none of their business, I have kept my previous name for work purposes - but bank if you are not
Credit cards
Passport
Car insurance
DVLA for your car log book
travel insurance
pension people
any insurance companies
council tax
electoral register
EHIC card if you have one
taxman (I told them but told them I was keeping my own name for work, they said they didn't care what I called myself as long as I paid tax against my NI number)
doctor
dentist
solicitor
I've been remarried over 5 years and utilities, mortgage, etc. are still in my previous name so if you are going to change it completely then you need to tell
mortgage company
ultilities
phone
house and buildings insurance
and so on....