We have been away for the last time in our caravan that has lived in France for some years now. For TV reception we have used an old Panasonic sky box, tripod and 80 cm dish which has always produced excellent reception even in the very south, But no longer. South of a line from Bordeaux to Lyon BBC, ITV and Channel 4 are not available from the present astra satellite.
However we met an interesting man who was receiving all of these channels down into Portugal as well. The secret , bearing in mind I don't know what I am talking about, is to use Satellite Intelstat 907 at about 41 deg W of south and an Icecrypt decoder from Amazon (about £60). The signals from this satellite are encrypted so you have to get the BISS codes from the internet and load them into the decoder box.
I have yet to do this as I will not be going to the south of France again. I pass it on for what it is worth and the dish size is not critical-60 to 70cms is plenty.