Am I missing something?!

[Skippernick]

I suppose you could call one a fuel overflow, but it's really there to drain rainwater away from the filler cap area.
It's just as well yours never sees rain, though you could have introduced water to the tank when you wash the bike.
It'd be interesting to see what comes out when you take the link hose off.

Well took the pipe off this evening, and about 10cc of runny white liquid came out!!!!
The tank stopped gurgling straight away as well