Sabrina and Clueless are indeed on at night, but as I am still in the US I don't know anything about Sky.
If I'm not mistaken, the website has a channel and time listing.
And I watched the old Degrassis sometimes, but they didn't show it very regularly on my PBS staton growing up, so I only remember a few things. That is available on VHS, and I think they're doing a DVD release of it as well.