You can't buy the O-ring on its own, you have to buy a full section of pipe which is about £30.
It will seal providing the other o-ring you have is in tact, you just need to cable tie the fuel line to the rail.
disclaimer: this is only a temporary measure
It only has one but will only seal with the cable tie, thanks for the tip
Managed to get a box of assorted ones so hopefully one in there, I would of measured my old one but being an idiot I dropped it
I have a spare bit of fuel pipe with the connector if it's the o-ring on there you mean?
Let me know how you get on. If not i'll take mine off and compare it. I go out to renaults alot that have had this problem. It's usually after a garage has done some work on it.