Insanely slow internet speeds

Solution
My knowledge of Fiber is limited due to a lack of experience. From what you've said it sounds like there is an issue with your setup. I'd call your Fibre company and have them take a look.
First, make sure your units aren't changing. There is a big difference between 67MB and 67Mb. One B is equal to 8 b's, so if you are paying for 67Mbps and you are getting 6MB, that's pretty much ok. 64/8=8. You are losing speed somewhere, but you are for the most part getting what you should. You should also make sure you are testing correctly. NOTHING else using the bandwidth and test with a speed testing site. Not trying to download something and see what comes through.

67Mb is an odd rate to pay for. Are you sure about the 67?
 


My units are correct and yes, the broadband im paying for offers speed up to 67Mb with an average speed of 50Mb, and I'm currently getting 2Mb with nothing else using bandwith.
 


I get slow speeds on all devices e.g. desktop, laptop and and mobile through using WiFi or ethernet. The internet is fibre. There are currently 10 devices connected but I would say max 5 being used at one time, usually less, around 2-3. The router being used is a BT Smart Hub and no modem is used.