I upgraded to Fibre over a year ago, and all has been reasonable starting with 29mb all seemed great from my usual normal line speed of 0.5mb to 2mb which I had been used to and had previously accepted being on the end of the line from my local exchange.
My usual fibre speed dropped to around 20mb which was acceptable, that could even be measured on any device I run over the WiFi connection, which is the way I connect all of my devices.
Occasionally this speed would dip, and I would reset the router, and it would return to around 20mb.
Recently this has dropped to a steady 2mb as taken from within the router, as well as tests, and resetting the router has no effect, it remains at 2mb.
Whilst it is still usable, its not acceptable, as I am paying extra for Fibre, when standard Broadband is what I am getting,
my voice line sounds clear, and my configuration has not been altered since Fibre was installed.
What causes this ?, I suspect if I wait long enough it will go back up to a reasonable speed again on its own