About a month ago the car had some major work done on it, new cylinder head, cam belt service, con rods, glow plugs and all relevant seals. The car was running fine, then 5 days ago it wouldn't start, it was cranking over, but not 'kicking in' so i thought it was a fuel issue. I had 3/4 tank and the evening before this the car was fine. The first thing I done was checked the fuel filter, it had been changed about a year ago by me. It was pretty black, so I put it back in but decided to get a new one once i'd got the car started. When I refitted the old filter, after 30 seconds or so of cranking, it started to kick in, and idle'd fine. Almost as if air was in the fuel lines, stopping it from starting. So i went and got a new filter, fitted it and for 2 days it was fine. Decided I was going to drive to Paris...bad move. Parked up in Paris for the day, came back in the evening and the same problem car was just cranking but not firing. Breakdown guy came out (French) and the first thing he tried was to whack the fuel tank from underneath while i tried to start the car. Again, after 30 seconds or so it started and was fine again. He said it was to do with the hot weather, fuel vapour and filling the tank to the max from what i could understand which seemed like a reasonable reason considering how hot it was, and the fact that I had filled the car to the max. However, once we got home, the next morning it done it again, but it eventually started without needing assistance. So i'm now thinking that the fuel pressure is being lost somewhere. So far all i've done is have a look at the pipes coming from the fuel filter, but who can recommend where i should start to solving this problem? Are there any common places that these hoses leak? Does the above issue sound like air in fuel lines?