We have the Tennants system and it works nothing special and nothing to complain about.
Yes you need to keep records, however we supply very little retail, we have focused on supplying Garages who themselves are registered with DVLA and therefore they keep the records and there info goes on the plate made. We were audited (along with several of our trade customers) by DVLA about 3montsh after we started and they were very happy with the set up and record keeping.
and Yes it is illegal to supply a "show plate" despite any waivers signed etc – not sure it has ever been tested in court yet though!
Extract from DVLA:
"Although the term ‘show plate’ was not recognised in law, there was clearly some
confusion as to the position. Since the introduction of RNPS, nearly a third of all
enquiries received by DVLA about the Scheme have related to the question of ‘show
plates’. Any doubts about the position have been removed by the Road Safety Act.
As the law stands, a registration plate cannot be marked as a “show plate” or “ not for
road use” simply as a means of circumventing the legal requirements.
The Road Safety Act makes it an offence to supply any plate bearing a vehicle
registration mark and designed to be fitted to a vehicle or trailer that does not comply
fully with the display requirements and British Standard as contained in the Road
Vehicles (Display of Registration Marks) Regulations 2001."