For the last few nights I have experienced slow upload speeds. I first noticed this when gaming, so performed a speed test which is when I noticed the 10Mbps upload speed - I am on the 200Mbps package and normally see slightly over 20Mbps upload speeds from speed tests.
Phoned up support tonight, who told me to reboot the modem, put the modem mode, then finally pinhole reset it - all of which did nothing to improve the upload speed.
I repeated the test on my mobile phone, several wired desktop computers and a laptop - the upload speed is consistent, regardless of device or connection.
I did notice that my upstream power levels for all four channels seem high - 48.3 - 48.8dBmv. I highlighted this to the advisor on the phone, but I might as well have been talking to a brick wall as he seemed to think that both the power levels and upload speeds were perfect.