Thanks for the replies people, I'm (temporarily) on insulin after having whopping great drip fed doses of steroids at Papworth for a possible transplant rejection or blockage. So my experiences of hypo's are extremely limited, but having read on here so much advice for hypo's I thought that 15g would do the trick, as indeed it did.
I must say that this insulin thing has to be treated with a great deal of respect, I've been previously balancing the Gliclazide and the jolly old Metformin for 12 years with a good level of control.
Keep calm and carry on,
Superchip