Buying car with mileage discrepancy

Looking at an MG TF, it was at 100k miles in 2012, 2013 it was mot'd at 20k miles.

It's currently sitting with a dealer who apparently bought the car off an individual not knowing the discrepancy after seeing 3 previous mot print-outs. Surely any dealer would do a basic check such as historic mileage?!

If its priced as a 100k miles car, would you still walk away? It looks very tidy and the MOT history is solid. They're offering to service, MOT it again, and free delivery.