We are once again experiencing drainage problems with the toilet and it has now been closed until we can get it sorted.
We have learned of other allotment societies using this model experiencing similar problems and so we may ultimately have to consider a replacement if a permanent soloution can’t be found.
In the short term we are trying to get a plumber up to the site to try and sort it out.
Until then it’s a matter of keeping fingers and legs crossed that it won’t take too long.