Hi there
Thanks for posting the link to your blog, I have read it with interest and must admit I did chuckle about the 'gaffa tape' lock in - which seems to have worked !
In fact you mentioned something that I hadn't actually thought about....
The bag that the worms were supplied in ... would make an excellent base filter, as its woven plastic, and therefore wont rot but allows the air and liquid to penetrate.
Great idea to put it at the bottom of the 1st tray to stop any worms heading southwards into the sump !
(though worms are wily little creatures and can squeeze through the smallest hole - Ive seen them coming out of the tap !!)
Also Im really glad that the slideshow helped with the setup.
Many Thanks
Ronnie