Thanks for the advice Jimbo and Rubjonny.
In the end, I never removed the ignition switch. My car was dying on me randomly with no warning lights and on closer inspection, I noticed that somebody had previously replaced one of the pins on the connector to the ignition switch. Probably the company who installed the alarm.ÂÂÂ

Why he didn't just splice into the wire I don't know.
Anyway, the replacement pin was a bit too wide so it did not penetrate very deep into the connector giving rise to a rather tenuous contact. When I tried wobbling the wire with the engine on, it just cut out with no lights. I'm hoping I've found my fault but time will tell. ÂÂÂ
