Thank you very much for that Five pot's will give them a go.
Might well be that Ratty, if it continues that will be the next thing we will check out.
We did pick it back up today they couldn't find anything else wrong with it, they drove it several miles and it has not done it to them,
My dad drove it back home tonight and it got him home, problem is he is now just expecting it to leave him stranded somewhere again as nothing showed up.
They did say it could have had an air lock and it has just sorted itself out? as it is auto bleed or something? with luck that will be so, guess time will tell.
Thank you very much for your kind help and advice with it.