Finally got my car back on the road following the DVLA's mistake to scrap it back at the end of March! The problem only showed up when I went to tax it in May and no records could be found of the car. I was advised by the DVLA not to drive it on a public road as the registration had a 'Scrapped' tag assigned to it. After many phone calls, letters, photographs of chassis numbers etc they realised they'd made a typo and transposed two numbers. My case officer at the DVLA was superb throughout (surprisingly) and I had daily updates from him regarding the investigation, according to him there has been a jump in this sort of mistake as they are still battling through the backlog from the scrappage scheme. Luckily I wasn't in dire need of the car otherwise the last 3 months would have been painful.
Just thought I'd let others know in case they find themselves in a similar situation.