Did not book in advance as wanted to see whether my car would be able to drive round the valley. It was touch & go, but in the end we went with Blackwater Tours & we are so glad that we did - it was fabulous, enhanced by the tour guides fabulous local knowledge, it made the trip exceptional. We visited loads of places on the tour & of course the guides & tour vehicles are able top go to places that you cannot go to in your own vehicle. The views were stunning, the names of the formations descriptive but what made was the guide. So much history, so many stories about every part of the valley, it was captivating & delivered in a conversational matter of fact way which made it totally understandable. We could have made a mistake & driven ourselves, the Blackwater tour was the way to get the most out of the visit