Folks
a quick one I have the above devices and also a historical BT Homespot 763.
I want to replace the homespot 763 which has one end wired into rooter and other end upstairs.
can I have two WiFi extender 1200 connected wirelessly to the SH2 and will work ok?
You probably can, but if you do they need to be far enough apart so that they don't interfere with each other. I certainly wouldn't recommend wifi extenders in the first place let alone 2 of them.
Either consider a proper mesh system or replace your hotspots with newer TP Link devices https://www.tp-link.com/uk/home-networking/powerline/