Stupid shower problem here. Basically the shower doesn't draw enough hot water to cause the boiler to kick in. Turning the cold water tap on usually helps to starve cold water from the shower and usually gets the hot water flowing.
I thought adjusting the mixer valve on the shower to give more preference to the hot water would help, but I can't see how to adjust it:
I've tried turning the copper thing in the middle anti-clockwise but it only turned about 5 degrees and has made bugger all difference.
Are there any other options?