This sort of confirms what I said about the first quote, however I don't understand what difference it makes in which country you have been issued with your EASA PPL if you can fly with no restrictions anyway (again, correct me if I misunderstood this).
I'm not 100% sure but I think that if your JAR license is issued in Spain, then you'll have to do everything such as renewals, endorsements etc. through the Spanish CAA. I don't think the British CAA will be able to do anything else besides automatically recognizing your license's validiy, a higer level of intra-state integration is probably still a only a chimera.
So, if you plan to continue training in the UK you might have to eventually change the state of issuance of your license. The process "should" be pretty simple and straightforward, as it already is a JAR license. Dunno if it's going to be inexpensive as well...
Cheers,
DG800