Corrugated polythene

I have inherited an 8'x8' greenhouse that has a glass roof but the side glass panels have been replaced by corrugated polythene. They had small children & a couple of sheep so presumably this was a safety move. Have just noticed 2 panels have been taken out by yesterdays gusts. Can't really see that this stuff will let enough light through but not sure about having the wit to replace it with glass. Any advice?

 

Excuse the means by which the woman who works long hours creates a flower bed but it'd the best pic I have of the g/h.

 

It looks like there are no horizontal glazing bars fitted to the wall sections so unless you put some in you'd have a heck of a job using glass.
Polycarbonate sheet in a small corrugated profile won't make a tremendous difference to light transmission and it's what I'd go for in a similar situation. Another alternative would be twin wall polycarbonate it would have better insulating properties although slightly worse light tranmission.

 

Thank you