Hi Guys, bit of an odd one!

Had my mark v for a bit over six months and never an issue, a few weeks ago when I started her up it was really rough for about 1 second like some one was jumping (very fast!!!) in the bonnet and the bace to perfection and off I went, then on tuesday of their week I tried to start her and it just cranked for about 5 seconds and was doing the same 'jumping' thing again, at first i thought that it was due to the fact that I hadn't let the glow plugs warm up before cranking so I warmed them up and turned her over again, same thing, this happened about 5 times with about 5 or six seconds of cranking per time, then when i was about to call RACV to come look at it of she went perfect??? I have had a couple of weeks off work and have been doing some longer trips no freeways etc, and the fuel was about/bit under 1/4 tank?

Drove to a friends about 1hr away and parked in the drive way and when I went to leave a few hours later there was a puddle (very small) under the seam between the drivers and rear doors on the drivers side, had a sniff and it smelt like diesel, but that may have been my imagination?? The feeling that i got was that the fuel had leaked out of the engine back into the tank or onto the road?

Anyway had it looked at at volksaffair (really friendly and only to happy to squeeze me in(gotta plug decent service when you get it!)) they kept her over night and no issues could be found, no leaks etc, seems ok at the moment,but a bit worried that there maybe an issue with it I do have a five year warranty that I got with the car so not so worried about the costs associated with repairs but i am worried that the cranking may damage the engine as its such a harsh sensation?

any ideas?

Thanks in advance
Sam