My idea is not high on the scale of priorities but will remove the threat of nonsensical prosecution for the non display of a free ved disc and will save money!
Currently most, if not all police traffic cars are equipped with number plate recognition kit [ANPR] and there are numerous static readers.These can identify vehicles without mot and insurance as well as valid ved.
My suggestion for a relatively modest but nontheless worthwhile government financial saving and also to remove the threat of prosecution for the non display of a free issue ved disc, is to abolish the need for historic vehicles to display such discs.
Police traffic officers will be well aware of the regs covering historic vehicle status and old cars are fairly obvious but ANPR would be the safeguard against cheating .
The number of historic vehicle on the road will be a matter of record at DVLA and the cost of issuing 'free' discs easily calculable.My own ad hoc guess is c£1m pa