Falling into this category is The Car King Pre-owned Car Dealership
(also trading as the Kingdom of Cars).
When I recently bought a car
from them the salesperson, Martin Stolz, promised that they would do a
full service on the car (they did a minimal service but I suppose I did
not really expect any more), that they would roadworthy the car (which
they did but only because they had to transfer ownership into their
own name so they could sell the car to meand luckily for me they had
kept a copy of the document) and that they would license the car for me
which they did not do. Apparently they only do this if you sign a
purchase agreement with them (i.e. you buy the car from them on terms).
Their advertising also promises that you will leave their premises with
a full tank of petrol. Again this only applies (or so they told me) if
you sign a purchase agreement.