Thanks, I might have misinterpreted their website - I read that as "if you get the grant, you qualify for this cashback, which is the equivalent saving of 20 a month, but we'll still charge 40 a month". Are you saying you're only being charged 20 a month? That makes it much more appealing - I know the net outcome is the same but I like to minimise my monthly running subscription costs across everything as they rack up!
Still seems like a decent deal to me overall, but I haven't done much research in the area yet