Just pointing out that assuming all allotment plots are a set length without quoting a width as previous posters have done could be amusing.
Q "What have you grown on your allotment?"
A "A row of carrots."
The site I am on tapers along its length, and is un-equally divided along its length by the main path/track, plots are five rod on the right, narrower side and ten on the left, wider side.
However the 5 rod plots are long, along the site and the 10 rod are long, across the site.
To get an accurate description of a plot you need to take a rod as being so many square yards/metres (30yards, 25 metres square) and as an interchangable title for the measures of pole and perch. I have checked this by measuring several plots on my site and doing the maths.
Once I realised this I managed to reduce my bill for a part plot described by the site agent as five rod to the realistic rate for three rod, which is what it measured out as by area.