Scary Moment!

86,500 miles, and other than a couple of new injectors after last years trip to France (???), no problems with my Td4. Then.......... last Thursday travelling up the M5 before Gordano Services, (the steep bit at the end of the Gordano Valley), lost power, engine warning light came on and as soon as I tried to pick up the slack, the engine cut out! Luckily, I made it to the hard shoulder. As I didn't want to sit there on a Thursday evening waiting for the RAC, I decided to try a restart. Ignition off, re-start no problem, no warning light nothing! Made it to the Services and tried again, no problem. RAC chap turned up, plugged in laptop and found nothing recorded. Set off again, same thing happened again heading up the Avonmouth hill. So, with 200+ miles to go, left the car for the recovery vehicle. Waiting for it now. No mechanical noises. Any ideas?
BTW - RAC and Hinton Recovery - Excellent Service! Thanks.

hole in the pick up pipe in the fuel tank, as you go up a hill the fuel moves to the back and exposes the hole/crack. soon as the hill levels out it covers the hole and your away