Hiya
I'd definitley recommend taking lessons and as many as possible to familiarise to the UK driving style as quickly as possible.
It's a fallacy (for the most part) to think becuase you've had 15 or 20 years driving in the US that learning it all here can be skipped or reduced to real minimum levels. I'll admit, i've thought exactly the same when I've driven in the US and Canada because everyone thinks they're a good driver right!?!
However, I certainly found driving over there easier than I'd suspect someone from there coming here. The road layout for one is great, wish the grid system was here too - although it's more visible in city centres I get the general drift that the 'logical' layout of roads there is much better than the logic used here.
My last driving trip in the US was Apr 2004 and I didn't have the US maps on my GPS unit so had to rely on print maps. Much easier to park up, work out where I was now, look at the map to see where i was, then look to see where i wanted to go, count up intersections etc and then drive off and count. once nearby to look again. Here, you constantly have to check and go down windy roads and it must be really confusing to a person who's never been or driven here.
If/when I do stay in the USA for longer than a holiday, I'll definitley take lessons an dlearn more. The amount of flashing yellow traffic lights I went through, didn't know what certain signs meant, tried hard to remember that able to turn right on a red rule etc I'm surprised I didn't get pulled over much more by the cops than I actually did!(im almost proud of my 4 tickets in about 5 days compared to how squeaky clean my USA family and friends records are!!)
It does cost alot for lessons here, I used to pay £12 a lesson in 1990 and the big BSM's were like £14 - but I'd say it's well spent if you can get as much experience as you can before you take the test.
Good luck!
DtM! West London & Slough UK!
P.S - I won't make you all want to slap me for telling you how many lessons I took before passing 1st time and beating me was my mate!
I'll keep shtumm!