I am sorry this will have to just be a description as I didn't have my camera on me.
I have just seen a spider upside down over my pond making a web.
It was 2cm long in body, top of abdomen pale yellow. Underside of abdomen was darker, with two yellow stripes running down the middle.
It had extremely long front legs.
I know that it is not a crab spider, and also it is a web spinning spider.
Hope someone out there can help.