[Bibio]

i'm not a huge fan of jubilee clips as you cant get them tight enough unless you get good quality fuel hose ones. normally there is a bit of excess on the crimp that you can nip up but it looks like they are well tight. you could try nipping it up with a pair of nail pullers by giving it a bit of a twist.

its strange how its intermittent as usually once something like that starts leaking it keeps leaking.