DS1 was moaning that his PS4 kept dropping connection, so to stop the moaning I got him an ethernet cable.At that point nobody else had bad connection. But now DS2 and I struggle to connect our laptops a lot or lose connection. I don't know about this sort of stuff but do you think it's the cable?
It could be that the wireless router isn't in the best position to get a good signal to the whole house. The Ethernet wouldn't effect the strength of the signal so the other option would be to get a repeater to boost the wifi around the house.
Are you losing connection with the internet, or with the router and therefore also the internet?
Look at signal strength indicator on WiFi on your laptop, it will vary depending how far from the router and thickness of walls/obstructions.
If signal strength is fine, then maybe it is bandwidth that is the issue. Now that the PS4 is connected reliably is it transferring quite a lot of data? Is he playing online games where it is sending little packets of data constantly?
Think it may be called packet loss.
Try running a broadband speed checker, see what data rate you are getting. Run it at different times, such as when PS4 is not in use, when it is in use.
The internet is cutting out and I wonder if it's something to do with the provider (sky). Try doing what the other poster said to check bandwidth although I think it's more to do with sky or maybe the router.