Berlingo 1.4i Petrol Intermittent Problem

[Nordo]

My daughter has a 1.4i petrol Berlingo (built Nov2000) for her business. Recently it suddenly dies while driving. After a minute or two it's all OK again. This has happened 2 or 3 times in the last week. Also she has noticed that she can now hear the petrol pump running for 2 or 3 seconds when she first turns the key on. She never heard this previously.

I thought it might be the fuel filter, but maybe some of you guys can shed a bit more light on the problem.

I've worked on a few cars over the years, but never a Citroen.

I have a Haynes Berlingo/Partner workshop manual.

Thanks :D