Dear Beagle,
The problem lies not with a current CFS category, but a current CFS category on SEP! The bit that is underlined in LASORS as of this year. From my own experience I found that even instructing on Tucanos did not count as although a single propellor aeroplane and all the basic EofC and S+L packages included, it was not piston powered. This is the main crux of the problem as a CFS category on anything other than SEP does not count.
In my own case, having completed the course with the training organisation you have referred to (who were very good), albeit under previous LASORS, the CAA pointed out that my A2 didn't count. They said I could have an FI(R) and that's it. Fortunately the FTO fought my case as I had passed a flight test including IMC and aeros and thus had these included along with a reduced (but non-specified) reduction in experience required to remove the restriction. As I said commonsense eventually prevailed but it took alot of effort from those helping me. H1.8(c) has now been specifically included to avoid similar such bunfights.
Nevertheless, the problems of an A2 on non SEP still exist. All I can suggest to guys (and girls) with A2s who are still in is to try and get someone in CFS to give you a check CFS check on SEP before you leave. Also when negotiating with the CAA, push to get applied IMC and aeros (you never know!) included at the start as it is alot more difficult - and expensive - to get it added later.
Best of luck to all as we are just trying to give something back.
Blakey