m0ther Congratulations!! Best of luck for everything on Monday - please post how your moving day went after! 
Welcome lubey and Fortheloveofscience!
We personally waited to get a survey done just incase something went wrong with the mortgage. We're also in a tiny chain - selling to a developer, and buying an empty property. Unfortunately, the vendor of the empty property is absolutely useless and couldn't care less if he sells or not, which has been an awful nightmare from the start. Hopefully your vendor isn't anything like him, though!
I've found solicitors and estate agents are generally useless, too, and require daily pushing. I have no idea where on earth we'd be if I hadn't chased them endlessly, honestly. But then we do have the complication of the horrible seller!
Sympathies to you lubey. We sold ours in January so we've been waiting a long time and I'm fed up now. We've essentially been waiting for the seller from April - June to answer enquiries, and then after that JUST to give authority to exchange. It would be laughable if it wasn't so infuriating.
We didn't exchange today. Apparently Countrywide require authority to exchange every day they attempt to exchange, despite receiving authority from him yesterday. And of course, as he's practically impossible to get hold of (today he was out "servicing his car" all day, and couldn't possibly answer the phone
), I can see us struggling to exchange at all. So frustrating all around.
They're going to try again Monday, which means I have all weekend to worry about it. 