broken greenhouse idea?

I have taken on an allotment that has an old small greenhouse, unfortunately its seen better days and the door is hanging off, and when i say hanging off i mean beyond all repair. other than that all the remaining glass panels are still intact.
Could I cover the door with polythene and use the greenhouse as normal or would i need to have a glass door?
As you have probably guessed I am a real beginner and would appreciate anyones replies

 

For most of the summer you may not need a door.Pictures would be useful and then we might be able to give you better advice with ref. to the door depending if the frame is wood or metal.
Nothing is beyond repair just depends on the amount of commitment required:WINK1:

 

Hi ninhydrin if your using clear polythene it should be ok as long as it lets the light in & keeps a bit of heat in there you should be OK look at polytunnels thats all they are covered with but thay are made to resist the damage that the sun can do to polythene, Polythene will become brittle over time with the suns rays on it, hope this helps Mick

 

A big bit of conservatory roofing plastic and a bunggee cord to hold it in place. Easy Peasy. Cheers, Tony.

 

I think this one is beyond repair or at least my DIY skills lazy dog haha but i will try and get some pics for you to see.
I think I will try the polythene or the conservatory plastic and see what happens, I will just put a few tomatoe plants in there and if it doesnt work this year then try another idea next year, Iv still got my garden to master yet with it being my first year so im in no hurry