Finally got through to a very helpful assistant at Sky who managed to activate my Discovery and Netflix accounts. This was the second person at Sky who had tried to help, the first was on the phone with me for 45 mins and tried all sort of fixes which didn't work, this second guy seemed much more aware of the issues so maybe it's worth perservering until you get someone who can help. It is a faff to try and get through to a human though.
