A couple of years back I switched from ADSL2 to VDSL2, the speed increase was great. I was getting 45-50mbit down and 10-12 up
These days I'm lucky to get 28 down and 8 up.

Recently we had a few issues with the landline dropping out, but the internet staying on (albeit slowly)
After reading endless posts about line quality and connection specs (most of which is way over my head) and discussing with now the possibility of using voip instead of the landline, I decided to bite the bullet and re-route my phone connection.
You see the house phone wiring is not pretty (its been hacked by all and sundry by the look of it) and we have 4x phone sockets and only use one.
The line comes into the house less than a metre from my office window, so I decided to bypass all the phone sockets and run a pair of wires (cat5) directly from the line-in to a pair of sockets under my desk. As I say, this is less than a metre distance. All joins are soldered and insulated so there are no dodgy joiners in the system. The master filter attached to the wall under the sockets, no other sockets in the house connected.

I still only get 28mbit down. 
Being a Now supplied Modem/router I do not have admin access to it so cannot check any settings within.
Chorus have checked the line as far as the gate and say its ok.
The exchange is about 100m from my gate.

At a loss now as to why my speed has dropped.