I was thinking about a chutney; love the stuff and can't it lasts forever. Spicier the better! I was thinking pickling them but can't find a recipe that allows you to keep out of the fridge, or one which keeps all winter!
Is that rhubarb in you picture? How come you've removed the roots as well?
I don't have an allotment, but do use the back garden in Peckham to grow a bit. Got summer squash coming out my ears ATM!