Well,
I've had a mad day of it today.
I ordered a new relay from Maurice (thanks mate it turned up today) and fitted it today. The drivers light went out after about 20 minutes, so this evening I......
Bypassed the relay
bypassed the fuse and fuse box
Fed a new earth feed directly to the ballast pack, thus bypassing all the car's - wiring
Fed a new live feed directly to the ballast pack, thus bypassing all the car's + wiring
All this led me to one conclusion......it MUST be the bulb, even though it's been doing it since I fitted it. So as a last attempt to pinpoint the problem, I swapped the bulbs...now the passenger's headlight goes out after about 20mins, proving it's the bulb.
So what's the chances of driving home one day and your drivers light goes out after 20mins. You buy a new set of bulbs and replace them. 20 mins after switching the lights on, the drivers light goes out, leading me to think it's something else....Just goes to show, just because something is new, it's not a certainty that it's fault free.
I have asked the Ebay seller to send me another bulb and when/if he does and I fit it, I will test the lights to prove my theory and confirm to you.
Thanks
Mike