Hi, I thought i would share the solution i came up with for internet connectivity while at our second home in France, we are only here ~3 months a year so preferred not to have a full time connection.
In the end i bought a sim card for Prixtel: Forfaits mobile Prixtel – Offre mobile sans engagement
it has the advantage that when we are not here the cost drops to 10 euro a month for the first year and then 15, it is also without contract.
I plugged it into one of these: https://www.amazon.co.uk/gp/product/B08B1VFHKB/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
which autoconfigured very nicely, you do have to put the sim in a phone first and disable the pin code, this is a one time operation.
I also bought one of these and put it in the loft: https://www.amazon.co.uk/gp/product/B09998P19L/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
this boosted the speed from 30mb to 55mb on the connection which uses the SFR backbone - obviously this will vary according to location.
Lastly i plugged a landline phone into the RJ11 connection on the back of the router and am able to make and receive calls using the sim card in the router.
I’m sure this is obvious to some, but it might help someone to find a solution, it took me quite a while to come up with something that gave me the performance vs price i was looking for.