Wow! I didn't even know youtube-dl worked with anything other than YouTube. I've always used get_iplayer. It's worth bearing in mind that not everything on iPlayer is available in 1080 or even 720 so if you want to test you've done the hack correctly try a recent episode of Doctor Who. The Good Life wasn't shot in HD and some very recent stuff isn't available at 720 either. I initially tried the hack with an episode of What We Do in the Shadows and something close DVD resolution and thought I'd not done the hack correctly. Then it occurred to me to try it with an episode of Doctor Who and I got 1080. get_iplayer can only get What We Do in the Shadows at around DVD resolution so I guess the BBC's licensing of that only allows them to put it on iPlayer at that resolution. Twelve Monkeys is still available on iPlayer and at 1080 with this hack.