Hi p2m welcome to the forum, but I'm afraid that the sky mini-dish (45cm) is to small for Hotbird. Would be better off with a 80cm dish (although you can get quite a few channels with a 60cm, some more with a 70cm). To get Hotbird (which has a strong signal, and is easy to find), first find Thor 1 west which is due south. Then move the dish east 14 degrees to Hotbird at 13 east, easy peasy.
All depends on where you are, location, north, south, east or west. The old Sky dishes were 60cm in the south, and 80cm up north. Try your old LNB first and see what you get. If no good try the other one.
According to SatcoDx they transmit 386 fta channels from Hotbird and the larger the dish the more you pick up, and also you must take into account how many channels will you lose when it rains. Mind you on a 45cm dish I think that 65 channels is pretty good, surprised me.
I think the 65 relates to signal strength. Sorry should've been a bit clearer. Think I got well over a 100 channels - probably more if I can get my cam working on some of the scrambled channels (with an official card of course). It was a bit weird that I kept adjusting the dish to get Astra 19E but even though the signal strength went up to 80 none of the channels came up - but the hotbird channels still came up.
I heard Raven say that their 70cm elliptical dish acts like an ordinary 90cm dish so maybe their 45cm dish acts like a 60/70cm dish. Or maybe not.