1966 4.2 2+2 Steering Lock Ignition Switch

Hi,
I am looking to buy a new core for the steering lock ignition switch. I contacted S&G Barratt but they dont stock them. I cant find anyone else with one. Do you know where I can get one?
(I "rebuilt " mine years ago, but now its cutiing out at its leisure, and I have to wiggle the key to get it to go again…)