Went to court for this a few months back, I actually got away with it as I had trade insurance but they hadn't updated the MID database with it, although looking back I was quite lucky.
DVLA have a permanent solicitor in Swansea mag court now and are hearing about 150 cases a day, their seriously clamping down.
Ridiculous law and one that needs sorting as to me if its taxed or sorned that should be fine.
You can't drive/park on the road without insurance anyway so why does taxing it make any difference?