Sadly I feel for you all.
Unfortunately I am in the middle os a tussle between BT and Plusnet at the moment.
Plusnet put an FTTC line in for me and advised I will get between 5Mbps and 11Mbps (I know this would never be possible owing to the length of the line from the Cab to my premises but went with it anyway). Plusnet also advised that my minimum speed gurantee would be 4.2Mbps down and 1Mbps up.
The line went in, 10 days of 'training' conducted, ahem, hmm ok... Low and behold the max speed being recorded is 3.2Mbps, circa 25% down on the minimum speed guarantee!
Plusnet contacted me to advise that I was below the speed guarantee and as such to contact the BT USO department to conduct a USO assesment and to follow the USO up. I contacted the BT USO department and they are refusing to help me as apparently I can receive over 10Mbps! Right, ok. I advised of the testing and results conducted by Plusnet and BT said if this info was inaccurate then Plusnet would need to prove this to be the case (well why they are telling me this I have no idea, its nothing to do with me). Plusnet are stating that the facts are in the recorded data, BT are having none of it, so both of them have left it with me to sort out.
What the hell I am supposed to do I don't know.
I have had this before with OR, whereas the BTw database was showing an inaccurate figure for FTTC which took me 3 years to get addressed, when it was resolved the checker showed the correct figure, funnily as reflected above, circa 2.4Mbps ~ 3.4Mbps. How on earth BT's figures have changed to something above 10Mbps is beyond me.
Looks like another 3 year fight in the making, at least I can cancel my contract with Plusnet without quibble, owing to their inability to provide me with the minimum speed guarantee, that may be a 'Plus' indeed.