I can't imagine any allotment holder being so short of space that they couldn't fit in a compost bin - or a builders bag for an emergency bounty (yes, bounty) of green 'waste'.
A truly traditional allotment holder would rather compost their children
than buy soil health in a bag from the 'garden centre'.
Most sensible allotment regimes would go quite justifiably apeshit if you burned fertility at the same time as gassing your neighbours with carcinogenic tar aerosols.
Never incinerate, never surrender (apologies to Galaxy Quest).
I assume you are valiantly squeezing the maximum produce from your home garden? In which case ditch (& compost) the flowers/bushes and annexe their beds (there are plenty of partner-convincing ailments they could get - especially if they are hogging the sunny part). Compensate by getting into edible-ornamental gardening - probably the only area where we are significantly behind other countries (especially the USA, weirdly).
Cheers.
PS. Have you ever noticed that any sign of blue sky seems to trigger something in pyromaniacs that makes them yearn for rolling clouds of carcinogenic smog? (exactly when you were hoping to start the kind of spring jobs that involve heavy breathing
).