Quick update:
Tried the ncam package as well, got everything working fine. To be honest, I don't see any difference between the ncam and the oscam setups, but not an expert in the matter.
Took me a while to wrap my head around the "play with stream relay" thingy, but got a better understanding of how these things work now.
In the Pure2 feeds I found a plugin called enigma2-plugin-camd-oscam-uk which does have the stream relay built-in and it works perfectly, set it up with a line for the SD channels for Sky.UK on 28.2E.
For the 19.2 Sky.DE channels I am using the ncam plugin from the same feeds (v14.6) and set it up with a different line for those channels so I have to switch between them depending what satellite I want to watch (but that is an issue with the lines I have, they don't support both the SD channels on 28.2 and the HD channels on 19.2 at the same time).
Managed to get things running in the end without the pre-defined lists from different forums/threads/posts. It seems that as long as you have the correct channel refs in the /etc/enigma2/whitelist_streamrelay file, all works fine.
Thank you everyone for all your replies and pointing me in the right direction.