Hello Lloydsky
My suggestions, for what it is worth, are:
1. You are used to the US so do your JAA CPL in the US, preferably in a neighborhood you know. Weather is so much of a factor here in the UK it may not be a satisfactory route, but in the US you could have your CPL done within a week to 10 days quite feasibly.
2. Do your Instructors rating in the UK. This will help you get used to operating in UK airspace, RT procedures and navigating in a different topography than what you are used to.
3. Try and find an school that will offer you an instructors position/work at the end of it. Plusses would be a school that does IR's and has a sim you can use as well. Then after a year of instructing do your IR conversion with same school. Whilst you are instructing it will help you no end with the IR to get "back-seat" trips on IR training flights.
I haven't done this myself but I am training people along this route and they remark that it is a formula they would recommend to others.
Regards, Porridge
PS PM me if you need further advice.