Did not give change of address to DVLA yet, what now?

It says you can be, not you will be. Fill in the bit on the V5 that notify's them that you have changed address and make a decision as to whether you want to lie on it saying that you moved a few weeks ago. If you have had speeding tickets etc sent to the old house you could be in a bit of trouble about it if you claim you only moved a week or so ago. If you have driven within the speed limit everywhere etc then they will never even know. It's rolling the dice to a certain extent but I really don't think you'd normally get a fine for it if you are offering the information, being such a long time might change that but human beings come with the inherent ability to lie.