Very helpful info.
I lose internet when phone reverts to tesco mobile, and when I edited tesco mobile settings the phone still reverts back to tesco mobile.(can happen 2 to 6 times a week).
I've only had this problem since I changed from Vodafone to my 48 .
Will probably look to changing the sim card as I've had 2 new Samsung and a 4s iphone and all had the same problem.