The air conditioning takes a good 10 mins before it starts to feel cold, is this normal? Other cars have had the air con has been cold more or less from starting.  

Mine has started to do that and I am presuming that it is low on gas. So I have booked it in to be re-gassed next Tuesday.

That was my thought.  I'm trying to find a garage that does air con and van read the system.

If your car is a non face lift then it will most certainly be the older type gas which is cheaper as the new price for re-gas starts at about £100 plus to re-gas, the price depends on how much gas you use.