In the end, I couldn't get the wooden one they had offered so I took a big black dalek instead. Has a b*ggar of a time building the d**n thing on my own! But now it's up it seems OK. It has several doors for harvesting which is great. I took apart the old box, the birds went mad around it! They must have a nose for the insects in there! There is a big pile of ready compost there, next week I will take some for potting and start to spread the rest on the beds.
I put a wheelbarrow full of non composted stuff in the new box, there is still a bagful to go on. My arms hurt like billy-ho this morning! I've not really room for several bins, as I only have a small plot.