Hallo @md123, welcome to this forum, and welcome to Europe! I am much less qualified to reply than people like Genghis - I am not half the aviator he is, and besides I am on the European continent, not in UK. I do have some experience though in listing aerodromes, and following forums, and should like to offer a handful of friendly small warnings, all well-meant of course:
* be aware that, contrary to the US, the vast majority of fields in Europe require prior permission - PPR - I remember some US'an pilots having great difficulty to accept the fact, but there it is... Never NEVER fly into a little field without having called before - and if you find no phone number, there might well be a reason for that. One possible explanation is that many small strips operate under very restrictive conditions, the most famous being the 28-day rule. Blundering unannounced into a field under that regime might bring trouble for the owner/operator!
* be prepared for the different units - as far as I know, the Brits express temperatures in degrees Celsius, and runway lengths in metres (just like almost all the world does). Not to mention altimeter setting in the elusive hP unit
* be prepared even for differences in vocabulary - for just one example, Denham is not an "airport" by any standard, and Biggin Hill could be called that only marginally. As I understand, the term "airport" is applied to almost all aviation terrains in North America, but in Europe and many other places it is reserved for the big fields where the airliners go.
Perhaps more relevant: for serious IFR flying, you might prefer something more than a basic C172 or PA28. But the basic SEP license will only allow you to fly a non-complex plane - no turbo, no retractable gear, fixed prop only. Any plane more sophisticated will require differences training, as I understand - again, I am not an authority. Do make sure, though, to save yourself disappointment!