Any advice on how to stop an allotment water logging?
Difficult one to answer that given the information we have to work on.
Any chance of a few pictures from different angles, soil type and is it on a hill/slope/hollow?
hiya, thenovice, welcome to the site ;D
our allotment gets waterlogged, as in paddling through water on the paths, it went over my ankle boots yesterday..we've sort of solved it by raising beds above it, that and pulling spuds as soon as they're a decent size, if we're getting lots of rain ::) ;D
I'm right by a stream, and I get waterlogged occasionally; last year some of my rhubarb drowned, and that's a plant that likes the damp. It is only an occasional problem for me, as the plot's well drained. Some of the lower-lying plots are waterlogged more regularly, and if I had one of those I'd build raised beds.
A lot depends on the situation. It might be due to water running across your plot, or clay soil, or all sorts of things.