I have an Indian airtel SIM which has a yearly pack that I keep active to receive SMS etc from India while i am in the UK. My dad got it for me due to the aadhar issue as my previous SIms used to get deactivated every few months

This was working well as I didnt have to keep changing my phone number on each trip to India

Looks like I'll have to start paying roaming fees now even for recieving incoming SMS.