That’s said it does find an available service, sometimes that’s SFR, sometimes Orange.
I use Prixtel as my SIM provider for my 4 G backup router. Prixtel runs on the SFR network and is contract free.
This year I have had the best service I ever had on a data connection … I had purchased a second user 5G CPE device second hand ..actually ex Eir in Ireland ..but identical to plenty available in CeX or Cash converters etc. ..cost 130 euro .. . Then an SFR .. 500Gb data card ..25 euro per month “without contract” and an additional 10 euro for the SIM .. It might be without contract and PAYG monthly ..but it needs a French Account . RIB . . You pay nothing in the SFR shop and the money is taken as direct debit about 2 weeks later ..With Your. SFR card in a phone you set up the "SFR etc Moi " account and cancel when you want .
I was getting data rates of 400+ Mb per second into all my devices Next year I just repeat with a new SIM card at 35 euro per month …
The service is instantly operational ..no delays
I believe in the UK it’s not allowed to restrict the type of device a SIM is used in.
Did not know that, I use a Lebara sim in a router in London just for security cameras and alarm system.