Am I reading this right? My friend just bought a house there and he said it's in zone 4?! I thought England was mostly zone 8??
I wouldn't think northern Scotland is zone 5. Must be a mis-statement.
Very unlikely. The US zones don't really fit our climate very well because although we don't get extremes of cold, neither do we get much heat. Zone 8 would be about right or even 9 since London has a microclimate of its own due to being built up. There are outdoor olive trees growing in some London gardens. Central London seldom gets any temps below zero (Celsius).