When I renewed mine to keep D1 last year I sent all the stuff off, they sent it back saying something wasn't filled in properly but unhelpfully omitted to say what wasn't filled in properly. I rang them up, the chap went through the forms - they must have copied them all on to their system before sending them back - and he said no, it all looks fine to me, just send it back with my name on and I'll sort it. So I did, and he did, and it came back every quickly then. But cost me two lots of expensive postage.
New van, V5c not turned up so after 4 weeks I rang them. They insisted it was still showing as "in the trade". I had watched the chap at the garage do the transfer of ownership online, then I taxed it online. They said I'd have to go and get another form (V62?) and send it in with the green slip, and allow another 4 weeks. Instead I rang the seller and he did the transfer again online, he said I was the second that week where this had happened yet all others done recently had been processed. Anyway, I then got the new V5 3 days later.
So I don't agree that DVLA need hailing. They need a blooming good kick up the jacksy so they don't keep wasting my time and money.