HELP - info on alien colonies sought

I hope someone can help me with this info. I'm keen to learn of any accessible self-supporting colonies of alien reptiles and amphibians in the UK. I'm planning to look for green lizards on the Bournemouth Cliffs next week (are they easy to find? is there a specific location?) and am also keen to see any midwife toad colonies around. I've already come across countless marsh frogs and (presumably non-breeding) red-eared sliders, seen wall lizards down in Dorset and stumbled upon a colony of edible frogs near my old work place in London (didn't try to catch any so presumably some could have been pool frogs?). I've also heard there's a site in Surrey which holds Alpine & Italian crested newts along with pool frogs, though it appears catching and re-releasing such beasties is actually illegal.

Despite the fact that I graduated in zoology (at Bangor University -well represented on this forum it seems!), this is purely for personal interest only. I've spent time sketching and photographing native herptiles and am now interested in searching out some of the aliens at large, so please let me know if anyone has recent info with site directions. Oh, and they would have to be more easily seen than Aescuplian snakes in North Wales!

James Hanlon