Hi Andrew - sorry to hear about your greenhouse
, same thing happened to me, i was just gonna give up on the plastic thing but i decided to give it another go. I reinforced all the joints with gaffa tape and stuck the rips in the plastic, i added some more guide ropes and weighed it down inside with growbags, pots etc. So far its staying up and is much more stable - now able to withstand the wind
But hey if you dont wanna do all that the netting idea sounds good too!!
good luck