A property on Rightmove at a guide price of £450k (reduced to this in April) was last sold in May last year at £305k. Unfortunately the sold details have the current photos attached so I can't see what it looked like before.
It is a fairly modern house so I don't think it can have been in too bad a state, I suspect it's had a new kitchen and bathroom and decorated throughout.
Does that seem a reasonable increase or is it as bonkers as it seems to me?