I thought it would be impossible to keep a US account open once I am a UK citizen??
Hi Becca. I just want to reiterate that just because you are moving to the UK and starting on the road to settlement, you do not ever have to give up your US citizenship or your bank account.

Also, as with all things in life, your goals may change. I moved to the UK to be with my husband over 9 years ago. I had planned on going the whole route, straight to naturalisation. Then we made the decision to move to the US and instead my husband is the dual. Anyway, what I am saying is that just because you move, it doesn't mean you have to cut off all ties to America. You still vote (by absentee), you still have to file your taxes and you can keep your bank account open as long as you like.
I am also an advocate of not rushing and transferring all of your $$$ into £££. You talk about giving your soon to be spouse access to your $$$. I would err on the side of caution with that. This is your money, after all. And considering how strong the £ is against the $, your $$$ may not last as long as you hope!
Have you looked into Bank of America? They have a reciprocal agreement with Barclays (a major UK bank) for free ATM withdrawals. There will be a minimum amount you can withdraw per day, however once you get settled and know how much money you need, then you can set up bank transfers for larger amounts.
Hope this helps!