Well, in case you are ever faced with this conundrum, I'd turn left. I favour the much larger and more interesting collection at Exmoor - even if it does have a bit of a home-made feel about it. The Wildlife and Dinosaur Park at Coombe Martin is more of a theme park - the animal exhibits are superficially a lot slicker and professionally constructed. But whoever is in charge at Coombe Martin has some strange ideas for exhibit-theming.
Haha, the first time I ever visited Exmoor with my mum and sister, we spent ages driving over the place to find it. It was only when we stopped on the side of the road, about to give up when we saw this exact sign!!