My 306 diesel (M Reg) would not start. AA man visited and after disconnecting the fuel feed pipe (to the carbouretter?) noted that fuel was dribling out rather than jetting under high pressure. I kept turning it over and it eventually started on 3 cylynders and then when I connected the pipe, it was fine. Runs OK. However, if left for more than about 5 hours, it will not start again. I got it going this morning by taking the high pressure feed off again and turning the engine over for a long time. AA man suggested it might be a leak in the low pressure return - is this likely? If so, how can I locate and fix it? Help DWH