I'm after a load of washers but not sure what they are in imperal coding they are about 4mm internal 9 outer and 1 thick. I'm crap at working out their coding
Here you go Sunshine.
http://www.engineering.com/Library/ArticlesPage/tabid/85/ArticleID/118/Washer-Size-Chart.aspx
The top washer which is a #6 has dimensions of 5/32" hole, 3/8" diameter and 3/64" thickness.
In sensible terms that is 4mm hole, 9.5mm diameter and 1.2mm thick.
So you need a #6 washer.
That's unusual because I've always found imperial washers to generally have a bigger diameter to hole ratio than metric.Cheers oddly I got some #6 and the hole in the middle was right but the outside was tiny compared to the original so I assumed #6 just referred to the bolt size it would fit.