When my previous car was wrecked in 2009 I transfered it to SORN to claim the remaining road tax. When I came to put the plate on retention I was told I had to re-tax the car. Re-taxing the car requires insurance and MOT to be valid on the day of purchase and luckily both were still in place (but only for a month, and the MOT would never be passed again!).I don't think it needs MOT anymore.
You need to build a good rapport with a local test station as I'm sure they could have helped you out here.
IMHO if you are going to put a car into storage or do any kind of long-term restoration or repair to it, or if it's literally just been crashed and there is any doubt it will go back on the road RETAIN THE PLATE IMMEDIATELY, before declaring it off-road, cancelling the insurance, letting the MOT lapse or claiming back the road tax.
