The prices on that site are based on the RPI, and are rather misleading. Some parts of the economy inflate far more than others.
According to that measure, the 3-bed semi in Cheltenham I bought in 1979 (and sold again 3 years later) for £12000 would today be worth £43,740... Actual price (even allowing for recent falls) is probably nearer £175,000 - £200,000.
Petrol in 1971 was £0.33 per gallon, according to RPI that would be £3.36 now. If only...