A very large spider, approx. 20pence piece abdomen. No obvious markings like Araneus diadematus, very pale/yellow.
No interactions present.
I reckon it's most likely to be A. diadematus. There are some examples of odd colour variations here -
Great page that Alan... and there is at least one spider on it very much like this one which even has the array of little black dots on its back.
So far, we all seem to be uncertain which species this is, so I think it's safest to leave the identification at genus level. For me it looks most like a variety of A. diadematus, but I can't be sure. A. quadratus is another possibility.
Entomologist and biological recorder
Lat/Lng: 51.393433, -2.358725
OS grid ref: ST751661
Horse chestnut tree base