Hopefully someone might know of such a service local to Cambridge but if not there are a few options. 1. He gets some simple neg processing equipment - worthwhile if he intends to do this regularly and finds a local mini-lab who can print reasonably onto RA4 paper. It is likely to have a slight colour cast
2. He uses the Ilford B&W service. Better option but involves using Ilford film and a mailer.
3. Have look in the B&W magasine. There are a number of B&W processors listed but none I could find in the Cambridge area.
4. Finds a local camera club that still has darkroom facilities.
best of luck