If you buy a house at above its market value expecting it to go up in value you have paid an inflated price....
I still don't see how you can do that.
If someone else offers £200k for the house and you offer £205k then you've paid the market price, the market price for anything being defined as "what someone [sane] is willing to pay for it".
OK, if the highest alternative offer is £200k and you come back with an
insane offer of £300k then you probably will be paying above any rational estimate of "market price", but surely to goodness nobody ever does that anyway.