1) Everyone is being moved to FTTP (full fibre), and copper connections are being removed. Fibre is faster, future-proof and not affected by things like weather.
2) Sky does not install or control the fibre connection; this is done by companies like Openreach and Cityfibre. However, you can complain to sky if they have done a bad job. Fibre has to be installed on an outside wall, and the router and wall-mounted modem will be positioned on the inside wall. Usually, this means the front room of a property; however, it depends on where things like telephone polls are located. Thus, it might be that the fibre had to come into your kitchen, and that is why the hole had to be at the countertop level, because that is where power sockets were.
3) Wifi is a radio-based connection, and thus it is perfectly normal for speed to drop the further you are from the router and the more walls there are between your device and the router. Moreover, the speed will not drop in a progressive linear fashion - it will drop quickly as walls block the signal strength.
4) If you have a white Sky Max hub, the simplest solution is to buy a Sky Max pod from ebay (Sky Max Pod Wireless WiFi Booster Extender SE411-UK). This will boost the signal between your router and your devices.
There are better solutions, but this is the simplest for non-technical people and doesn't require more Sky subscriptions.
https://www.youtube.com/watch?v=BUB9ArVrTko
