2.4Ghz travels through walls well, but what goes through your walls can also go through your neighbours as well. Hence this band is usually overcrowded which slows the connection to a point where streaming becomes intermittent.
5Ghz is a lot weaker, so does not have the problems above. It also uses a wider data channel.
In short you should try to connect the box via 5Ghz WiFi. If you still get the same problem then some kind of direct wiring (Ethernet or Powerline) is the only option.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV6), Talk Anytime Phone, VIVID 350, Virgin PAYG Mobile