Was driving down an unlit country road and was really struggling to see, so I flicked the left stalk up for what I assume is main beam, think I accidently double flicked it as the headlights seem to change upwards and light up the road ahead - brilliant, so what is the difference between holding the stalk up and double clicking it ? a bit baffled ?

I no what you mean mate, when you hold the stalk back it seems brighter than just main beam. I think it must put the foglights on as well or something!

when you hold it you are switching on the main beam and dipped beam if you hold it like that for mor than a few seconds you will damge the plastic lamps cos of the extra heat also you will shorten the headlamp bulb life

My Mini is the same as the ST - when switching to main beam ,dipped goes off, so I can only see far ahead not immediately in front of the car. It is crap!

yes what you said is what I have noticed, dipped goes off and you have a dark spot in front of car BUT have that all important distance lit-up view which is what you want for unlit very dark roads, you can always switch the front fogs on to light up the front of car. So can I have these on when there is oncoming traffic or should I return briefly to dipped ?
Think I understand now, parking car up and testing this it appears that the lights suddenly point upwards as though the reflector moves, but it must simply be that as you say the dipped goes off leaving main beam on giving that appearance but vision is FAR BETTER than having both on ie holding the stalk up.