I agree, am trying to get them to correct a typo on one of my classic cars V5's, not the VIN plate which is correct, and a year later still getting more and more forms to fill out asking for more pictures and information.
All it is is the build location code at the end of the V5 which for every vehicle built at abingdon is G rather than the 9 on the V5, they all say G! so it is obviosly a transcription error or typo.
DVLA make much bigger cockups than a single digit...
About eight years ago i needed a car NOW so i went on ebay and looked for something cheap with tax and mot. I spotted a Seat Ibiza SDi 1.9.
I went to collect it, paid the guy cash and brought it home.
He gave me the V5 to post off to DVLA. Later that night i was filling in my part to pop into an envelope and noticed that it said it was a five door TDi. I thought it said on ebay that it was a TWO door SDi? I know i'd locked the front doors, but couldn't remember if i'd locked the rear doors...
As it was gone 11pm and about -3 degrees i decided i'd chance it and check in the morning.
The next morning i went outside and looked at the car. It had only TWO doors. I popped the bonnet and removed the engine cover that had in large letters either 1.9 SDi or just SDi on it. I then checked the manifold for any signs of a turbo. There wasn't one. TDi has one, SDi doesn't!
Next i checked the VIN and engine numbers against the numbers on the V5. Thankfully they all checked out.
So happy that i didn't need to lock the back doors i went back in the house to grab my phone and out again to take pictures of the engine cover, the exhaust manifold, the VIN, the engine number and views from front, back and sides. Printed off copies put them into an envelope along with a letter explaining that some details were wrong on the V5 and please see enclosed pics. I gave them my home phone number, mobile number and email address so that if they had any questions they could contact me quickly and not have to rely on snail mail. I also told them that the pics were copies and they didn't need to be returned.
About four weeks later a new V5 arrived with the mistakes rectified. I had been expecting problems if i'm honest, but there weren't any. A couple of weeks later a second envelope arrived from DVLA with my pics and a DVLA 'with compliments' slip.
Maybe you should have told them there were several or bigger mistakes and not just a wrong letter?