Roaming worked fine in the UK but on returning home I switched it off and the phone didnt connect to 48. Tried to do it manually and it wouldnt connect. Went through APN and entered settings as on the instruction pages here but when I click Save it does not save it. Ive updated the phones software and also taken care to ensure the APN settings are exactly as instructed with spaces, commas, etc but it still wont save it. The phone is a Xiaomi Redmi 12.  Ive tried to manually reconnect to the network just now but it doesnt even find it and it wont let me connect to the 3 network either. 

Kind of pulling my hair out at this stage as the APN just wont save and I have no network whatsoever. Anyone got a suggestion of what to try doing?