This car is a bit of a mystery - the Turner register reckons it's chassis 60/366, which makes it a MkI from 1959/60, which were indeed made available with Climax engines. They also claim that its registration was GWE777D, which is a licence from 1966 - in the UK you can't have a registration plate issued after the build date.
The car was also for sale in the US in 1987 for $19500 - the seller claimed that the car had spent time in Singapore, where it received the alloy body. So possibly it's a '59/60 car exported to Singapore and then re-registered when it returned to the UK, although these days the routine is to issue an age-related plate. Maybe that wasn't the case in '66.