Hi Niel, I presume it's the small metal clip attached to the mounting on the inner wing ?. If so soak with plenty of WD40, You will notice the clip is made with a right angled tab, you can grab this with a plyers and gently riggle this left and right, The clip is like a horse shoe and it holds the pipe tight against the flange, it should release quite easily. the next problem is un-dooing the union at the top of the flexy pipe. Good luck !
David 8228