Declaring SORN is simply a matter of making the declaration, most usual way is online, or by completing the form that reminds you your tax is about to run out. Any road tax already paid is then refunded to the nearest complete month. So you lose out in favour of the DVLA. You retain the V5, the vehicle SORN status is then recorded on the DVLA website for the world to see, and for ANPR to check and issue a penalty if that untaxed vehicle is clocked out and about. They must reap £££££. A printed confirmation used to be issued, don't know if they bother these days.
As for keeping a vehicle taxed, I pay a little bit more and do it by monthly direct debit. It's a bit of a creaser giving the DVLA a yearly or 6 monthly windfall. I'm a great believer in Pay as you Go, rather than money up front. We all know what a little empire and cash cow the whole business has become.
I'm expecting a berger rant as to our elected representatives and their hands on our throats.....
Swarfy.