Progress...

Works laptop -  tick

Second monitor working - tick

second monitor slaved to laptop - tick

What a first world problem...I've spent a week moaning that I couldn't operate on just one screen

today I decided to stop moaning and fix it...the guy in PC world laughed when I acted "girly"....
"how does your laptop connect to an external monitor"
"plug thing with two screwy bits"

But he knew what I meant and there was the required cable in the box

so the next first world problem ... the laptop I'm typing this on doesn't  fix with screwy thins so I'm off to locate an HDMI cable