No phone signal but got Data signal

I’m currently tipping at a site 1 mile from the main road in the New forest and I’ve got a strange one [emoji848]
Got next to no voice phone signal on both mine and works phone both on EE , yet iPad EE as well has 2 bars of 4 G data
Not complaining as the office can’t call me [emoji6][emoji16][emoji16][emoji16][emoji16]

Sent from my iPad using Tapatalk

If they are both ‘old school’ phones - voice and text not smartphones they might only be 2/3g. I’m not sure if every mast has all standards on or if they put up new masts for 4/5g and eventually retire or upgrade others later.