Reliable Valves OEM alternative and piston rings

I will need to replace a few valves. No idea yet how many, but there will be a few. I've been searching eBay and can't find any. I am in Canada. And the piston rings.. The replacement cylinder block is going to have the sleeves deglazed. It came with pistons and rings which look really good. I think the pistons are mixed up. The rings are moved around in the pistons of course. Ideally new rings is best, but..... The prices are high. Does anyone had a success using old in great shape rings and piston sets on deglazed cylinders? Link to reliable valves replacement?

Item numbers. 391695240743 and 272545681374 on the UK bay of fleas.

Pistons. 252432890646

Thank you! There are always things available in Europe or in the USA. Not so much in Canada. I think I will have to start checking UK eBay more often!