I’ve ordered from this company recently and received parts quite quickly.
https://www.lojadearmas.pt/epages/96...hString=Slavia
Also from Chambers…
https://twchambers.co.uk/airgun-spares/slavia/
The country store also does the piston seal…
https://www.airgunspares.com/catalog...sult/?q=Slavia
I believe the parts for the 627 should be interchangeable with the 618, 622, 625.
All the best
CZ 200T/200 S Hunter/200 S Green/Slavia ZVP/612/614/615/618/620/622/624/625/627/630/631/634/ZVS Perun 734/CZ236-1/Tex3/86/Brno ZII/ZV3/ZV4/VZ47/APP661/Relum/Mars 618/Stella 518/Predom 188/170/Yunker 1/2/Lov21/Baikal IJ22/IJ38/Vostok/IZH61/IZH53M/MP512M/MP654K/MP661K