IO:
You hit the nail on the head in your penultimate post, I suspect a lot of IR's don't have suitably equipped aircraft to fly the GPS approach. I have a PA32 which I use in airways but does not meet the requirements for the trials. At this year's PPLIR AGM (which I suspect you were at) where a presentation on the trials was made I got the impression that there were quite a lot of us in the same boat, (or aeroplane!)