Have a look online for how your parish manages allotments, if not available the parish clerk should give you a copy. It should also be stated in the agreement about notices.
There might also be a clause if the land you are working is farm tenancy, which means a high percentage of the land should produce food, livestock is not normally included. If it is a farm tenancy, you will not be covered under allotment use, but if you are not going to manage it all, all year round, you are breaking the terms of the tenancy. Read the smallprint.
There are several properties near me which come under farm tenancy so the owners have to grow food and not use the land as garden only.