I guess you would have a great variety over your side of the pond, but one of the nicest and for us, well priced are Weaver hatches made right here in NZ, for NZ conditions. Good solid, durable and can also be custom made to your requirements.
I would imagine you would find them with
Google, but let me know if you can't and I will get a web address for you. They have been recently bought by another company in NZ and can't remember off the top of my
head whom. But it will be in a mag here somewhere.