Complex sentence: Great Britain is notable for its relative lack of snakes, with the European Adder being the only poisonous snake to be found there, but the other notable snakes Grass Snake, Slow Worm and Smooth Snake.
Split into simpler sentences: Great Britain is notable for its relative lack of snakes, with the European Adder being the only poisonous snake to be found there. The other notable snakes found in Great Britain are Grass Snake, Slow Worm and Smooth Snake.