Saturno 500 inlet and exhaust valves availability

[KAB]

Hi folks

I have a Saturno that has in a previous life, suffered a cambelt failure. All 4 valves are slightly bent, with one valve guide having a small crack.
Does anyone know if the valves/guides are common to any motor car or motorcycle and readily available? Otherwise has anyone got any spares.
I appreciate that the Dakota are the same valves as the Saturno, and equally obscure.

Thanks for your help.

Cheers
Keith