Now, I need to sort out a different issue. I have a Zgemma twin tuner receiver box. If I use a mortised dish and the box is configured to receive tow satellites, let's say Astra 28.2E and hotbird. If it moves to any other ones, how would it pick up the other satellites if they are not in the box configuration please?
Try not to fall foul of planning rules, the biggest dish size allowed on a domestic building is 1m (sometimes not even allowed this), any bigger it will need a ground mount nearby. The best dish you can get on a house is a Masterfocus MF90 (99cm high) with about 2.6db gain over other 90cm (103cm high) dishes (breaking the rules?), or about 0.4db less than a 1.2m. These dishes are hard to get, only one stockist, and I'm not sure if they are made anymore.