Well I called Gatwick yesterday, because frankly, I was getting slightly confused by everything I read, on every forum, and everyone's take on it.
The advice, from them, in my OWN case, which may be very different from others, is go JAR, prior to July, 5 years, then EASA conversion.
And yes it appears that I can save some cash by doing it this way, although that is not the prime motivator for me.
Keeping legal, if possible,is.