Sounds like a simple task but it is very much the opposite.
Our 1967 Jaguar E-Type 2+2 door catch may look the part having been fully refurbished but upon closer inspection you’ll see the small spring is a broken. Typically, this spring is probably the most important aspect of the mechanism and is almost impossible to source on it’s own without buying a completely new unit.
Tommy has managed to reproduce the spring, strong enough to withstand the strains that is required. It is times like this where the talents of a classic car restorer really shine through. It may be simpler to buy a new one to fit but it’s much more cost effective to utilise the skills that you have available to you.