I think it sounds like you're doing everything right, ultimately unfortunately it just takes time for them to learn and know that outside is the right place to go.

The rain and wind doesn't make it any easier, I know that Hugo will pee very quickly and run back in only to need a poo a couple minutes later. Its just a case of pre-empting any accidents and big praising outside when they go.

Re carpets, I got the stuff from Pets at Home that if you use straight away gets rid of smells and is meant to mean they wont go there again, it seems to work on my carpets (eek well I hope it is and I'm just not immune to the smell) you have to get it straight away tho.

Good luck and for what its worth I think you're doing it all right!

Leigh (and Hugo) x