Hi Friends

Some advice please.
Recently I bought a 85-91 HW77 long stroke .22 with 25mm internals. Serial number 1141455. A friend has taken the gun apart finding the breach seal,piston head and spring need replacing.
He recomended a spring make but he couldn't remember the makers name LOL. Describing the spring as black coated in grease and supplied in a tube LOL.
He recomended buying the parts from Hul Cartridge. Normally I would have ordered a V-Mach kit and my buddy would have fitted and tuned.
He said he would make the guide and top hat. I was hoping my buddy a retired gun smith would have spares or obtain the parts. Should I buy individual parts as suggested from HC or try and obtain a V-Mach kit if I can find one or buy a different make kit but from where.
I'm not keen on waiting weeks for delivery because of the plague. The gun is in bits at my buddies house.
Any suggestions please.