I remember me and my brother getting excited when torrent speeds used to touch 200 kbps. Good days.

Are you in London? My 1Gbps link gives 800-900Mbps in these speed tests, and I'm fine with that. It's a pitty that some of that is unused because I need to use a VPN.

When I lived in a small town, my 500Mbps would give me >400Mbps consistently.

Where are you in the UK that you can get 300 but not gigabit? AIUI, you’ve either got Openreach FTTC (caps out at 80mbps), Openreach FTTH (1gbps), Virgin (1gbps) or various alt nets (usually 1gbps)

Is it cheap?

That's about the same speed for me (in US), and I could get gigabit, but I feel that the ~double cost isn't worth it.