Thanks you all for the very helpful replies. I've only today picked up all the messages since none came through my normal email route. I must have failed to tick the box asking for replies to my inbox.
Anyway, the solution for me was to buy a Chromecast dongle. I plugged this into the back of the TV in the HDM2 port and downloaded the app on my Asus tablet and followed the instructions. Amazingly (to me anyway) it all worked fine and I was able to watch an afternoon of sport in great clarity and in full screen.
I don't think that I'll bother trying to connect my laptop for now but might try this later. Unfortunately this doesn't have an HDMI port so I'll have to fiddle with that as well but guess that if I download the Chromecast app then it will be just added to the network.
Still I'll think about that later. Meanwhile I've got where I want to be so thanks to all who helped.