Bit of a waiting game really. 14 days time limit to send to reg keeper. If your new house owners have binned your post (real nice of them to do that) then if an NIP has gone to your old house and been binned then 'potentially', the fact is un-answered will lead to a summons being sent for not replying. This may or may not go to your old house, depends on the speed of DVLA admin updating records. If your new house owners bin that too....well, you need to sort things before that.
For goodness sake get a post office diversion set up so none of your old mail goes missing. If only to stop your life (financial etc) being at the mercy of someone else.
You could contact the police in that area explaining the circs too.
And on the other hand....it could well be it all fizzles out to nothing and you got away with speeding, if in fact you were?