When I bought my My current Gen1, which I’ve had for over ten years now, it already had a “Slip on kit” fitted and it ran superbly with it.
However, having previously had the “Full Monty” on a previous Gen1, I decided to upgrade. Mike was kind enough to do this for me down in Saltash. I then sold the “Slip on Kit” in the “Full Monty” box to BJohnD on here. This was at the end of 2017.
It’s not beyond the realms of possibility that BJohnD may have sold this on again? Equally, there is I suspect, quite a few on here that might have done the same upgrade over the years and as I did, sold the removed “Slip on Kit” in the “Full Monty” box.