I used to get 13meg now its 9.7meg

[#1]

I moved over to ADSL2+ in December and I got 13meg during training and it settled on 12.5 in January.
In February it was always 11.97 (never any other number - seems like a cap was in place)
I checked a couple of weeks ago and my speed had dropped to 10.92 meg (always 10.92 never up or down on that)
I checked today on a couple on BT and Speedtest and now its 9.7meg
The only thing I've done is swapped my Plusnet router with my Netgear a few times because I can't get an open NAT on the Plusnet router but the older Netgear alway gives me about 1meg less speed.
It seems that every time I've swapped routers I've lost some line speed in the process.
I'm now on the Plusnet Thomson v8 as I've stopped playing my online game.
Can anyone help
Here are my router stats (my ping is always around 12-16ms)
thanks guys.
Link Information
Uptime: 0 days, 5:47:37
DSL Type: G.992.5 annex A
Maximum Bandwidth (Up/Down) [kbps/kbps]: 1,124 / 13,236
Bandwidth (Up/Down) [kbps/kbps]: 1,131 / 12,439
Data Transferred (Sent/Received) [MB/MB]: 62.20 / 259.89
Output Power (Up/Down) [dBm]: 12.0 / 20.5
Line Attenuation (Up/Down) [dB]: 11.0 / 27.0
SN Margin (Up/Down) [dB]: 6.0 / 7.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 82 / 336
HEC Errors (Up/Down): 20 / 1,321

[#2]

Hi NatTheGooner,
Can you tell me if you're using any extension cables/sockets? Do you have a test socket you can plug into?
Jojo

[#3]

Hi Jo
No extensions.
I've got a shielded ADSL cable plugged into a filtered faceplate on the master socket. I've got no other sockets or phones in the house - super neat and tidy now.
I'm down to 8.5meg today.
I raised a ticket and the guy asked me to run a few speedtests and phone back - I've run a few but hadn't had a chance to call yet.

[#4]

Could you remove the faceplate and plug into the test socket using a normal filter. Let me know and I can run some tests once you do that.

[#5]

My phone socket dosen't have a split face plate (1980's house)
I fitted an ADSL nation filtered faceplate wired straight onto the BT line - no joins or extensions.