@Davcla if you are on a long copper line the speed that can deliver will be limited nothing to do with Sky it is simple physics. You do not say how fast the connection tothe hub is but let us say the hub is connected at 50Mb/s it is inevitable with a family of 6 at times there is insufficent bandwidth to go around. You mention Sky boxes watching a linear channel uses no bandwidth, downloading catch-up however does while it downloads and watching an App like Netflix definitely will. Someone watching Netflix in UHD will hog roughly 25Mb/s. Watch in HD drops that considerably. Online gaming does not take a lot of bandwidth but downloading one game update will likely knoock every other family member off. Sky hubs are simpke machines that deliver data on a first come basis so some basic family rules are going go be required.
The other issue is WiFi signal strength around your home. Poor WiFi coverage is probably the most common question we get in the forum. In many homes a single Sky hub cannot provide a usable wifi signal in every room due to the layout and type of construction of the property especially in older homes. Assuming the hub is in the best possible position which is out in the open on a surfsce then the only answer is additional wifi sources.
Your choice.is to either buy Sky's add-on WiFi Max bundle which can supply up to 3 extenders see https://www.sky.com/help/articles/sky-wifi-max or buy your own wifi system and use that instead of the Sky hub's WiFi.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
