I hate being pedantic, but in period the car was always known as the 'Jaguara' . There are 10 references in Motor Sport to sprints and hillclimbs between 1952 and 1957 which all refer to G Parker's Jaguara with no mention of Buckler. Doug Nye's definitive history Powered by Jaguar also refers to the car as the 'Jaguara' although he does say it had a Buckler frame.
I suspect that 'Buckler-Jaguara' is a later invention to describe the car, possibly by someione selling it.
It would be more appropriate to title the thread either 'Jaguara' or 'Buckler-chassised Jaguara' or possibly 'Gordon Parker's Jaguara'