FIXED IT!!!!

Here was the problem.

Firstly, as we discovered above, i had the Master Avionics Swithc off by defautly. So, creating a shortcut for that (and putting it ON in the defautlt flight) fixed half the problem - that is, that the DOTS appeared on the ADI, but no magenti intercept bar.

Second half of the problem, as that I had the radio in the default flight set to NAV. It turns out that it needs to be set to GPS. I created a toggle switch for NAV/GPS and found that switching it made the magenta intercept bars disappear.

So, in the defautly flight I've now got the Master Avionics ON and it set to GPS.

Thanks for all your help guys, MUCH appreciated.