Hmmm looks like I will stick with 23mm then, seems a few people on here use them and get along without too many problems. Think my clearence on my bike would make 25mm a problem anyways, may just get them on, but would not be much room.
My current tyres are Continental Duraskins, but they do seem to get punctures most times I ride in the wet, despite myself keeping them inflated to around 100psi or just above, for whatever reason, I seem to struggle to get 120psi out of them, the presta valve just spits my pump out at anything above 7bar pressure.
Still reckon those GP3000 winter tyres could be my best bet, I know they are expensive but only a few pound more than the GP4000.