The Allotments Regeneration Initiative, a happier-times product of government funding, has a semi-abandoned website where it is still possible to get hold of its useful fact sheet Affordable Toilets For Allotments, which The Shed insists on keeping, despite the head gardener’s long-standing hard line against going into shit processing when we have a perfectly good flushing toilet.
At the time of posting, it can still be found at
Click to access affordabletoilets2010.pdf
Meanwhile, attempting to load a pdf of it here in case the link breaks in the future.
affordabletoilets2010
hack4hire 
All the ARI factsheets are available on the Barnet Allotment Federation website at http://www.barnetallotments.org.uk/ari-factsheets/