I'm disappointed, I was looking forward to hear about the refurb.
TW Chambers on the internet have all the gear you would need mail order.
Main spring, leather piston seal lubricant and all other lubricants. Plenty of others offer similar service. I would say you could do the work in an afternoon.
But I hear what you are saying, so could suggest BSA airsporter/Mercury, as they are from my era and I know they are powerful, robust and fit your spec. should be plenty used examples about. See what your gun shop has in and try them for fit etc. You should be able to pick up a combination and have a bit of back up in case of bother.
See what they have available and ask on here before purchase to get some comments etc.
