This post is just for information to others who may have a similar problem in the future.
Basically my headlamps started acting up a year or so ago, whenever I switched from high beam back to low beam the lights would sometimes go out altogether for a second or so, often longer before coming back on. As you can imagine this is a little scary at night! So, after a little bit of testing with a multimeter & a circuit diagram I concluded it was the column multifunction switch that was at fault so I replaced it - and it solved the problem.
Anyway, a couple of weeks ago the same problem started to occur again. No problem I thought, so I ordered another switch, fitted it & the problem was still there! I was not happy that I was several dollars lighter without having solved the problem. So, got my multimeter & circuit diagrams out & carried out a few more tests. Didn't take much more than 30 minutes to establish that this time the "flash to pass" relay was at fault. Ordered a new one, replaced it & lights are working as they should again now.
The point I am trying to make here is that never assume that the same problem occuring again will have the same solution as before. It was my own fault for not taking the time to diagnose the fault properly & methodically. I consider that I have now learned my lesson. Don't wanna see any of you guys make the same expensive mistake as I did.