It has been nearly 30 years since I last drove in the UK, and I will be solo; for the record I Drive about 25k miles a year in the US and — other than NYC and Boston —-am quite confident and competent ;-) .
I purchased a UK Garmin in December in anticipation of this trip and have updated the maps. At home rely heavily on my Garmin.
My only concern about driving in the UK is the first hour, and the first roundabout.....
I plan to spend six days in south/mid Wales in late September, mostly on an ancestor hunt with some scenery chasing thrown in. I can either (a) pick up and drop off a car at LHR at the end of my London stay, or (b) take a coach to Cardiff, and do the pickup /drop off there.
Cost-wise it seems to be about a wash. So, which would be better: Leaving LHR and starting out on motorways to Hay-on-wye, or picking up at CWL or Roath?