I have Sky in one room and and get Sky in another without paying Multiroom �10 per month.
I have a digi sender plugged in to the spare scart on the back of the sky and the digi receiver plugged into the spare scart on the second TV. GigaAir 2020 is the one I use, but there are several on the market (about�40).
Maplin stock several digi senders, and I imagine some TV outlets would. But (big but) you can only receive the channel you are watching on the main set on your annex set. You can watch on the second set with the main set off and control sky from the second set. ( a second Sky remote is also a good idea)
If it's a case of two people wanting to watch different channels then multi room is the only answer.