Possible case of CGT on PPR ?

Someone told me that is an owner occupier of a PPR ( ie their long term home ) sold it for a exceptionally very high price to a developer, because of its city centre location, CGT may be payable because it sold above the "market value". Is this true?

You only get PPR on the value of your house as a home if you get paid get for its development value which is in excess of its normal market value than this is taxable

Thanks for the reply, but if the property sells for a very high figure at auction, is this not its market value ?