I use these tyres all year round. Heavier and slower than other tyres I have but they have been - touch wood - puncture free. Feel safe to ride on also. I have them on my MTB and on my hybrid.
is it me or is it just the back tyre that catches a flat?
If you cant get Greenguard, it might be worth you considering Delta Cruiser +..... 700x28 is only £11.99 at Chain Reaction with free del. They're the reflective band Reflex version as well.
£34.51 Delivered for a pair from Bike Discount