@jay_s_uk Everything is working again! Thank you!
Z offset looks ok. I'll monitor on further prints.
And I have centered the print, simply by changing the X5 to X0 in the 'M208 S1' line (M208 X0 Y0 Z0 S1) and adjusting the X size of the bed in the slicer. (I clearly don't know enough to safely set zero at the center of the bed at the moment).
The printer already had a macro for WiFi ON and I just had to change the credentials to my set. I have commented out M587 in config.g .
I do have a couple of other unrelated questions but I should probably start new threads for those (unless you want to continue here).
Thanks to both of you for your gracious replies and patience with my lack of knowledge.
Cheers,
Derek