I like making research for hard to find items, but I haven't found any leather seals for your pistol. Depending on the size of the main and breach seal, you may have some luck with vortek @ air gun source:
http://www.airgunsource.com/custom-parts-and-tuning
Or you could try making your own, do a little search on Google or on this forum, IIRC some members here have some knowledge about that. I checked the CZ/Slavia Czech site, but they don't list any replacement parts for the ZVP.
I saw good comments on the quality of that pistol, I hope you'll be able to get it shooting well!
Good luck
