My insect pages list the web sites that I know about but I don't think they include photos of eggs, just larvae, etc. My main insect page with links and index is
http://www.fishpondinfo.com/bugs.htmDragonflies leave sheddings of about 3 to 4 cm long, not 0.5 cm which are probably from some aquatic flies like mosquitoes, mayflies, etc.
I get on rocks and trees these cellular mini bee hive sorts of things. I'm pretty sure that they are produced by a red spider here in MD, USA so they could be mite or spider eggs there in the UK too. If they don't have little cells but are different, can you describe them more? Perhaps they are insect eggs.