Post office mate for less then a fiver you can find the address with the reg number
Just tried the DVLA website, and unless you didn't sell it with the reg plate in the pics they don't have any record of it.
Not much help huh??
I just went to the vehicle licensing section. All it will tell you is if the tax is due, which gives an indication if it's still on the road, or if SORN has been declared.
Unfortunately, it doesn't tell you where it is!!..but I knew that anyway.