Reddit mentions of TP-LINK (Archer VR900 V2) AC1900 (600+1300) Wireless Dual Band GB VDSL2 Modem Router, USB3, Cable & 3G/4G Support

u/the_x2i, seems this is not possible with standard functionality on BT Smart Hubs. I found a link supporting this:

https://community.bt.com/t5/Home-setup-Wi-Fi-network/How-can-I-prioritise-my-PC-internet-over-the-rest-of-the-house/td-p/1933930

Standard ISP provided routers typically do the bare minimum and are configured for mass market to work in the majority of homes. If you need prioritisation features then you'll need to find a router to replace your current one, likely one that can be used for a DSL connection if you're on BT, then with the spec you need.

I replaced my BT Smart Hub a couple of years ago after getting sick of going back and forth with them on how bad it was. I went for this one, but price, features, ease to setup, are all things you'd need to consider for yourself: https://www.amazon.co.uk/gp/product/B01N2LSLMH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Edit: spelling is important

Are you using the provider provided hardware? I was pulling my hair out with with the plusnet provided kit's constant drop outs. Got a TP link modem router to replace and have had no problems since. FWIW https://www.amazon.co.uk/Wireless-Connections-UK-Archer-VR900/dp/B01N2LSLMH/ref=sr_1_3?keywords=TP-Link+AC1900&qid=1567964325&s=computers&sr=1-3 Easy set up and it has been rock solid in performance. That said, if you are only getting 7mbps it is likely the average speed you will get.