o.k. I've done as requested and removed and reinserted the SIM Card and I still do not have that option listed in the SIM Toolkit App. This Sim Toolkit APP on my phone has no cogwheel nor Tesco associated with it. It is merely listed as SIM TOOLKIT.
I was without the ability to make/receive calls and texts again today for most of the day.
I literally can't spend much longer messing about with this. There is either a fix or there isn't. For most of the month by months end having changed to Tesco Mobile I will have been without the ability to make /receive calls and texts.
I will be left with no option other than to switch provider. This is not acceptable at all.