no problem, discovered it a couple of years ago trouble is most of us only get hold of MOT certificate numbers after we have purchased the car which by then could be too late!
 
I bought my Ibiza FR at 3 years old and was the 4th owner - however the private seller told me and produced evidence to show that the first owner was the dealership (pre-registered), the second owner was his father at the same address and the third owner was him.

So in this case I wasn't put off especially as the price was good. I've had the car for nearly 4 years now so 4 owners doesn't look quite as bad.

For this car if there's no explanation of why there's so many owners and evidence to support it I wouldn't buy it tbh.