You no longer have an EASA PPL, as the UK left EASA since you got it, and you didn't transfer it to another EASA country. So what you have is a lapsed UK-FCL PPL(A). Ignore what it says on the front of the licence!
With training as required and a skill test, you can renew that as soon as you want - pretty much any UK flying school can do that for you. You will want a class 2 medical first ,but then you can let that lapse back to a LAPL medical if you only want and need LAPL privileges, but at any point it becomes a full PPL again just by renewing a class 2 medical.
You can fly a G-reg aeroplane on PPL privileges anywhere in the world, you can't automatically do so on a LAPL or with only the LAPL medical, because it's a sub-ICAO licence.