Update: Following on from your suggestions I changed the battery to a new Halfords HB005, this seemed to solve the problem and the car has started and driven fine since, useage has been fairly regular.
Anyway today I attempted to start the car (to take it for a service ironically ) and its the same old story, all i'm getting is "click" and nothing else. The car was used the day before yesterday.
So i'm thinking, either the battery is flat again or its the starter motor contacts (but seems unlikley as was working fine before).
What would be the best way to check to see if the battery is flat, and if so, does this mean there is an electrical problem somewhere to drain a brand new battery in two days? What would be the best way to go about diagnosing what the problem may be?
Any help would be greatly appreciated, cheers
James