Im thinking of making a feature in the garden of two tanks  in a wooden frame were i can feed and clean from a back door can this be done due to winter weather etc and if so could someone please give me some details as it would look great in the garden.

Thanking you

If you insulate the tanks and provide heating during winter, the fish should be fine. Try to keep them away from direct wind.

Feel free to make a post of your own in case you have an unrelated questions like this

A couple of months usually, but they can keep changing colors throughout their lives, especially black colors tend to fade.

I would just like to add, in case someone sees this with the same idea.
My parents put two tanks outside as a water feature (no live stock in them) and I believe due to the weather one of them has a crack now and would not be useable for live stock. So I would personally not suggest keeping a glass tank outside for keeping livestock, for this reason alone.

Other factors as already mentioned would be heating - otherwise the entire thing could freeze, which is bad for livestock- it could be rather costly to heat it and to insulate the tank properly would possibly mean covering the glass sides, so it would render the idea of a glass tank outside rather pointless.