As posted on another thread, fresh start this morning, delete everything on every device and start again.
The phone was not connected to the TFT.
I would recommend having the manual for each device, open and readily accessible for viewing i.e. on a laptop.
Read through the instructions first and then refer to the relevant sections as you proceed the set up.
If it says press a button for 5 seconds, read the separate following instruction that says "now press the same button once immediately" to pair the satnav.
Again, I have set it up on the dining table, all working as required. Switched off and back on and still all ok. The test comes later when I put it on the bike!
Thanks again for the help and advice.