Pick up a Samsung Galaxy S8 or S10 from a used phone retailer. They have dual sim capability, can create hotspots, and can hardwire to a TV using a type c to hdmi connection.
You can then cancel the data only sim contract for your tablet as you can link to your phones hotspot using WiFi.
I don’t know what the cost of an Oyster dish is or a repair but using local mobile sims for the country you happen to be in offers far more flexibility and you can stream all over France and Spain and not be reliant on a satellite signal which you may loose in southern France depending on dish size and will definitely loose in Spain unless you use a different satellite and a decoder box.
The other option of course is to take with you several DVD box sets and watch those if you have no satellite signal and cannot use mobile WiFi. Or download loads of stuff before you go away. Make sure they are downloads without any expiry limits such a Netflix home produced stuff, iPlayer,, Prime home produced stuff, Disney+, etc.
For me in France and Spain (and Portugal?) there is no way I would want to be either dependent on U.K. roaming allowances or satellite dish signals but others may have a different view depending on personal lifestyle and needs and wants.
We did have a dish in the past when we had a caravan but that was a 90cm tripod job that worked all over France and even in northern Spain but those were the days when we parked up on sites and put up and pointed the dish manually with a satellite finder. With our motorhome and touring around we wanted other solutions. It’s just a pity your Oyster dish has failed but given it appears to not be the first time a good solid back up mobile WiFi system would seem sensible and provide flexibility.