It is particularly odd how the little things in life can be majorly annoying. The "My phone number" field in Android being blank or "unknown" is one of them. It has been driving me nuts ever since I discovered it.
If you go to Settings, About phone, Status then you will see that the third field down from the top is "My phone number". Unless you are somewhat lucky it will say either "Unknown" or be blank. How annoying is that? Very!
So tonight I went on a quest to solve the annoyance for once and for all.
The solution, believe it or not, was my iPhone Although, to be fair, it doesn't have to be an iPhone specifically. Any handset that will allow you to set "My number" up on the SIM will do.
The specific instructions for an iPhone are as follows:-
Press My Number
Enter in whatever number you want, you can use the +44 notation
Pop the SIM back into your Android and you will see the number that you programmed.