Many faults with Humax remote controls can be fixed by removing the batteries, then pressing the “0” and “OK” buttons together for 30 seconds.
I’ve no idea why or how this works bt it often seems to.

Yes you can but you’ll need to have a multi output LNB (normally a “quad” with 4 outputs. Each decoder requires a seperate connection to the LNB

As many as you like. If you have 4 or fewer decoders you’d normally use a “quad LNB”, for more than 4 decoders we’d recomend using a multi-switch system.

We use Vatc17 or RG6 for most installations, you could use Vatc19 for most installations.
For satellite broadband installation we use WF or CT 100, this is the best standard size co-ax cable that is available.

In Brittany a Sky zone1 minidish will be fine. A generic 50cm dish will do the job equally well.

Not for receiving UK channels in Brittany but don’t chuck you freeView box away as most will work fine for receiving the French digital terestrial channels.

Yes, a Sky box will work fine for receiving the main UK channels without any card or subscription.

Yes, in fact that is what we recommend.