Well not really, garages don't get classed as owners hence why there is a "sold to the motor trade" box to tick on your V5.
However its not unusually for sports cars to have a lot of owners. People buy them not realising they are impratical, thirsty, noisey etc and get a shock when they have driven it for a few weeks and sell on fast.
However the fact the guy couldn't shift a low mileage 06 model for £12.5k is a bit strange...
When you buy Lambo's & Ferrari's its actually very very suprising when they only have one or two owners. They get bough by speculators looking to turn a quick buck out of the latest car and people who literally only want to own them for the summer etc. Don't automatically assume that lots of owners means bad things about the car...........I don't think I've ever even looked how many owners my cars have had, if the car is mint and a good price, I buy it, simples.