The location of the land at ELF is not conducive to efficient mobile phone reception. I have been using Orange, ~ now EE for some 20 years here but signal availability has reduced over time.
Oct 10th 2020
My new mobile is a,Fairphone 3+,and has wifi calling, which is a first for me and that does permit EE usage.
For some blurb on the ethics see:- Fairphone 3+ supply chain
Feb 2021
I've made some updates to https://en.wikipedia.org/wiki/Fairphone_3
Nov 2021
Inherited a second FP3+
Jan ~ Feb 2022