I bought a cat C Corsa 1400 sport from our local salvage yard a few years ago... Put the front bumper back on and changed the head light. Then took it for a MOT, then went the post office to get whatever form it is you need to apply for the docs and the tax application form.
You then need to go to your local dvla office, mines Chester, go with your insurance, Mot, tax application form, any proof you've got that the car's yours.
Its about £18 quid for dupplicate docs, Jobs a gooden. The car is then legal on the road, about 6 weeks later you should get a form through saying you can't have the V5 for this car until its been for a vic check. £36 quid for that and then you should be able to apply for the docs...
Once Vic checked, you can apply for the £18 quid back you spent on appling for the docs
Vic check doesn't inspect the repair work carried out... they only check the car over to make sure its the right car, ie ringer, cut and shut etc... takes less than 10 mins