I never met John but we spoke on the phone on several occasions, and I always found him very helpful and feel privileged to own two of his air gun conversions, a PCP Webley Mk.11 Service and a .177 CO2 Webley Senior, I believe the only one he did, the other 8 being in .22. It was done specifically for Richard Duncalf, 'Redair' as was, now sadly deceased, from whom I purchased both items, and has the stamp 'J Walker Number 10' on the trigger block at the request of Richard, even though John only converted 9.
These two items will eventually have to go as part of my collection disposal, but I'm in no hurry to part with them.