OK we have an answer and a ‘Top Tip’ from my friendly auto electrician.
With a multimeter set to volts, connect red on the meter to red on the coil and black on the meter to black on the coil, crank the engine with ignition on.
As the rotor arm goes around you should get a ‘pulse’ on the multimeter, no pulse = dead distributor and guess what, yes it was dead.
Swapped it for James’s 123 distributor and now it fires up. Just need to do some fine adjustment with a strobe light and we should be good to go.