This is one thing that really gets on my nerves at the minute, went to buy an a4 today which was hpi clear but after vosa checking it there's been over 80,000 miles taken off the clocks possibly up to 120,000 going by previous mot records. Told the owner (garage owner) who said they didn't know about it and was going to get in contact with the person who took it in but surely a garage would know?

 

Tbh mate unless you've actively attempted to keep the mileage down from day one its a pretty pointless exercise as you've just rightly pointed out a quick VOSA check will reveal all.
I'm sure those cars suffer from issues with the instrument cluster so that could explain the change.
Mix in a few dishonest sellers and there's your answer.
Usually when you buy a second hand car they put the little sticker over the clocks disclaiming the mileage.

 

There's a billboard advert near me for "Digital Mileage Correction". That annoys me too as it just seems to promote clocking.

Are they actually going to get much business for genuine purposes?