Sounds like you have a drain, a very basic way to check is connect a multi meter in the line and see what the draw is, then start pulling fuses until the figure drops to something of the norm, then you can isolate the problem to a specific area.

Strange you should mention it as I was talking to someone the other week who had brought a new Focus, and he said it had a problem with the fuel pump constantly running which he had to take it back to the dealer for.

I presume this is a "Connect" you are talking about?

I am guessing the problem was present before the work took place?

Martin