Having read Denis Wilson's blog entry where he found a small fungivorous creature living between the fungal gills, I thought I had better have a closer look. Sure enough there were signs of something living there. Some parts of the fungus had been eaten and there was a network of fine webbing over the gills.
Closer examination found the culprit - a small caterpillar which I measured at just 3mm in length. I have tried to get a better shot but the caterpillar has since crawled off and hidden somewhere within the fungus. I will attempt rearing it but I'm not too sure on my chance of success. If I manage a better photo at some stage I'll update this entry.
White hairless caterpillar with dark head capsule
An update to this post can be found here.