I own one allotment approx 7 x 30m and another I rent at £10 pa.(20 x 10m).
In effect, this gives me one large 'L' shaped allotment. They are well
drained, when I laid a concrete and breezeblock base, the drop was 25cm over
3m.
No useage restrictions, I have a tarmac'd area, which is handy. A couple of
neighbouring allotments are devoted to chickens, they enjoy lettuce that has
run to seed. At least I know the eggs we eat are genuine free-range.

Bertie