LadyLily,
Since you seem to be doing a rather thorough study of prices and financial aspects of making the big move, let me mention one thing you may want to check up on before you go. Retirement funds and benefits.

While it is still possible to collect your US social security from overseas, there is also a "gotcha" in the form of the WEP (Windfall Elimination Program), which reduces your US SS benefits if you are eligible for any sort of overseas government backed pension. It hits many overseas Americans, though I'm told there may be some way around it with adequate planning.

It's also useful to know that, if you're exempting your overseas salary from US taxation, you won't be able to add any more money to your US IRAs, 401Ks or other retirement savings plans. (There are similar retirement savings plans available in the UK.) And there is always the issue of the exchange rate for the dollar, which can be a real problem for retirees abroad.

Retirement may seem a long ways off right now, but trust me, it sneaks up on you. In the end, you wind up cobbling together bits and pieces to try to arrive at a reasonable retirement income. It might be worthwhile to do a little planning before you go. (And maybe you can report back here on what you find.)
Cheers,
Bev