Killian,
Keeping three species of Bombina in one enclosure as demontrated in the website you mentioned is absolutely unbelievable to me....
They will procduce hybrids! Nothing really desirable!?!
Can you trust people mixing all together, not caring about consequences?
My proposal from own observations in the natural habitat is only to mix:
Bombina variegata and Triturus alpestris
or in a second enclosure Salamandra salamandra and Bufo bufo.
Bufo viridis needs more dryness.
And never forget the differences in size!
Just have in mind, that an adult Salamandra has a mouth, T. alpestis fits in perfectly......
My experience is, that people always try to have a species mix in an enclosure, disabling them to care perfect for one, but semiperfect for all!
Why not limit to just one or max. two species that are perfect for keeping together?
Just my two cents.....
Michael
P.S. Concerning your try to keep Lacerta strigata in an outdoor enclosure in Ireland: Have you ever compared the climate in their natural habitat with those in Ireland?
They need long extremely cold winters and hot, dry summers! This seems to me a little bit conflicting with the conditions in Ireland - does it?