Do the CAA's recent changes to medical requirements mean I wasted my time getting a medical?
No, I don't think so.  I believe there is a distinction between a UK PPL and an EASA PPL.  UK PPLs are defined purely by the CAA and only permit flying of aircraft outside the scope of the EASA licensing regime, such as some vintage and home-built aircraft.

The CAA proposal applies to the UK NPPL and PPL licenses not to the EASA PPL (with the exception that it may apply to pilots flying non-EASA aircraft in the UK only).

As it stands it is still necessary to have a class 2 medical to use the full privileges of an EASA PPL, although as footnote 1 says the CAA "aim to influence EASA in considering reviewing the medical requirements for EASA Private Pilot licence holders flying EASA aircraft".