Hello. I'm not a tax lawyer. I'm a UK citizen and a dual qualified US/UK lawyer practicing law in the US. I mostly advise entrepreneurs, business people, and British-American couples/families on US (and "some" UK) immigration law and those common legal matters affecting UK expats in the US, and US expats in the UK. Tax is one area I try to avoid though, apart from the basics.
"My understanding" (this is not legal advice) is that so long as you are working outside the US you are exempt from paying US taxes in income up to approximately $97,000, though you still have to file a return. You can also claim a credit for any UK taxes you pay against any US taxes you owe above the $97,000 threshold (but not below it of course).
I too hope to move back to London in a few years to practice law and will be facing some of the same issues as yourselves, though I doubt I'll earn over the $97,000 threshold!
Good Luck.