If i had the option, glass would win all the time

Glass is my vote!

Thank you for replying

Polycarbonate is a MUCH better insulator but it will only last a few years whereas glass will last virtually for ever or can be easily replaced.
Ideally go for double glazing, but like the other advice above, glass every time!

I would also go for glass, you have a choice of horticultural glass or toughened glass, both have their advantages and disadvantages, ie when horticultural glass gets broken you get big shards of glass which can be dangerous, but are easier to clear up than the toughened glass which breaks into thousands of tiny beads, which are a b****r to clear up, especially if they break over your borders, Derek.