@Hmohmo how are you measuring speeds? If it is on a device connected to the Sky hub by WiFi you are probsbly measuring the speed of the WiFi connection in your home which is lergely outside Sky's control. To check the speeds to the hub reliably you need to run the test on a device connected by a Gigabit Ethernet cabled link.
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.
=========================================================
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
