Thanks to all again for your input. I feel a lot more comfortable with all this now - I've learned a lot, thank you.
To update quickly, I went for the Three 3-2-1 PAYG deal, and the new SIM arrived yesterday. When Mr B got home from work he restored factory settings on the old iPhone and set it all up for me. I can now (if I want to!
) make and receive calls, ditto texts and emails. Mr B has also set my facebook up (he clearly thinks this to be an essential; I only look at it really for one particular group I am in!!).
I am having a play with it today and will go through the settings later on with him so that I understand fully, but data does seem to be switched off as far as I can see.
I am going to keep my old number (assuming that process goes as smoothly as it seems to be). I know there is no logic in this, given that only a handful of people know the number (and know not to phone me on it as it is rarely switched on) but I have had it years and am fond of it...
Getting the PAC code from Orange was a doddle, and the instructions on the Three website were also quick and easy. I am now waiting to hear when the switchover will happen. This will be the final frontier in getting me onto the new phone...
With this 3-2-1 thing I can apparently buy add ons, for various prices, which give me much more in the way of data etc. and last 30 days. Mr B is suggesting that this would be a good move for our upcoming holiday, in as much as I could leave the iPad at home, just carry the phone, and look at all the usual web sites without worry of running out of credit. It's a thought, but I am not used to web browsing on such a small screen...I like my iPad!
Thanks to you all again, you've really helped me!
Brava