I have lost all products??

Resetting your devices wasn’t a great idea. you should have just fired up the Desktop app, your devices were fine. Now they are not.

I followed the instructions from Sonos. Looks like I've wasted £3000

Actually, the “instructions from Sonos” on resets are spelled out quite clearly right here:

I think all of your devices don’t support BLE so the new app will not see them for WiFi connection 

plug the playbar into Ethernet and follow the reset instructions above 

Wow that’s a great FAQ, never seen that before. Sadly the Reset Instructions page doesn’t refer back to it, which might help.

I enjoyed listening to music on my Sonos speakers. I'm not a computer buff. I expected the products to last longer than 8 years.without complicated intervention.

They do - indeed Sonos are still supporting many products from 15+ years back. Sure, there’s a software issue at the moment but the speakers do still work and are still supported. 

They might be supported but it is beyond my knowledge to resolve the problem. 

Ahh, different problem. Since this is a user community, a polite request for help usually gets a better response than any other approach. 
 

Since you’ve reset your speakers they are, in effect, new products - they have no details of your network, etc. You need to install them again, as you did when you first bought them. 
 

As suggested above, it may be best to start with any that you can connect with an Ethernet cable and then get the wifi connections going. 
 

If you need more help and advice, there are folk on here that are willing to try to assist you. 

I've tried all that and still nothing not able to upgrade. I'll chill this weekend or I would bin them through frustration.

Thanks for the reply.