well done, but just to echo what others have said - the house is yours when the keys are in your hands and don't bank on it till then. We were sale agreed twice and had sellers pull out before we finally got our place. This is not scaremongering, its just advising you dont set yourself up for a fall.
Get your booking deposit in asap, ensure sign goes to Sale Agreed, likewise on websites.
Get your solicitor in gear and get on their case keeping them moving (email is often best means of contact). Get your mortgage side of things sorted out, all paperwork in asap.
Get a survey done, explicitly ask him to look for any asbestos or lead piping that might be around, as well as the usual stuff.
Shop around for mortgage protection and house insurance - LA Brokers, 123, FBD all good prices.
Good luck with it!