The British Isles are situated at too high a latitude to have a well-developed reptile fauna. There are only 3 snake and 3 lizard species in Britain, of which the Smooth Snake and Sand Lizard are very restricted in range. In contrast to warmer countries where lizards can be common garden creatures, British reptiles are generally only seen by people who go out into the countryside to find them, or chance upon them on sunny days. The Slow Worm is the only reptile that does well on the edge of towns, where it will often set up home in compost heaps in gardens that border natural habitat. Warm sandy heathland habitats in the southern counties are the only place in Britain where reptiles can really be considered common, or to reach any significant degree of population density.
The heaths of eastern Dorset and western Hampshire are the only place where you can hope to see all six British reptiles in a single day. That said, some are not easily seen at all, even in the correct habitats.
Derbyshire is home to all 4 of Britain's widespread reptile species, although seeing them is often down to good luck. None of the reptiles has a county-wide distribution, although they can be locally common.