I think that's right Durhamjen - they can't really start negotiating until they start the process formally and they are scared to start the process when so much is uncertain. If they start the process early next year the end point will be just over 12 months off a general election and they will be worried about that, for sure. Cameron/Clegg government passed that act of parliament that makes a snap election difficult (you have to have 2 votes of no confidence in the government, so they would have to vote that they had no confidence in themselves).
But before you start a negotiation process you need to be clear in your (collective, team) head what your aims are, what your range of good/acceptable outcomes looks like, and what your strategy is going to be. Suspect they are a long way off that. Trouble is once they launch into the process they are in a very, very weak position and that does not help if you are trying to negotiate. You also have to analyse what the other team are trying to achieve and in this case one of the aims of the EU must be to make it look like a very painful process for any other country that thinks about leaving.
There's also the Scottish problem, but the massive drop in N Sea oil revenues, announced yesterday will take the wind out of Sturgeon's sails. And the Irish question - how can we possibly "take back control of our borders" when one of them meanders through quiet (and, currently, peaceful) Irish farmland, with all the locals enjoying the freedom to travel to and fro to shop etc.