There has been much activity of late with companies offering 4G solutions to customers in the countryside under a Govt funded scheme.
Here’s one
(there’s a whole thread about the Bouygues offering here which is worth a read).
Orange too have a 4G offering.
Steer away from Satellite - its grossly expensive.
Many of the sites will provide a coverage map which is constantly changing as new facilities are brought on board.
Technology has also moved on with 4G routers. Don’t be misled by the apparent lack of a 4G signal to your phone… the 4G router aerials are far more powerful.