Not in the UK, but in Europe, I guess you can relate to that.
I have a router dedicated to an US VPN and a Roku 1, I generally get around 5mbps with it, it's enough for video streaming.
The monitor (a video projector really) I use is 720p only.
Netflix Roku App: I tend to use only the US version, the local version lack of content, it work GREAT, Netflix in 720p has a bitrate of 3mbps.
Plex : I have a lot of local content I like to watch, It's local and some isn't available on streaming services.
Youtube : I only use the application when I want to cast something from the PC or the phone, this app suck really, it's so sloooow.
VideoBuzz : This is a youtube client, it work better, also support reddit video, I use that function on /r/Documentaries .
TorrenTV : You install the client PC side, you drop magnet link or torrent file on it, press play on the roku and it stream the video, really really usefull for new episodes I can't get via legal means (http://torrentv.github.io/)
Watch Disney Channel/Disney XD/Disney Junior : I have user/pass for an US cable provider, it allow me to watch live tv or on demand content.
FOXNow: Require an US cable login, I use it to catch new Simpsons/new Family Guy episodes, there also too much ads.
And ... that's it :)