Connected to the test socket as suggested. Old results quoted, new ones below. No errors anymore so my extension is clearly a bit dodgy! Might have to leave it connected to the master and go wireless with the xbox.
	
		
	
	
		
		
			Uptime:	0 days, 1:41:07
DSL Type:	G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:	1,211 / 8,133
Data Transferred (Sent/Received) [kB/kB]:	0.00 / 0.00
Output Power (Up/Down) [dBm]:	12.0 / 19.5
Line Attenuation (Up/Down) [dB]:	13.5 / 24.0
SN Margin (Up/Down) [dB]:	7.0 / 10.5
Vendor ID (Local/Remote):	TMMB / BDCM
Loss of Framing (Local/Remote):	65 / 0
Loss of Signal (Local/Remote):	20 / 0
Loss of Power (Local/Remote):	0 / 0
Loss of Link (Remote):	0
Error Seconds (Local/Remote):	101 / 0
FEC Errors (Up/Down):	0 / 588
CRC Errors (Up/Down):	0 / 0
HEC Errors (Up/Down):	0 / 0
		
		
	 
Uptime:	0 days, 0:27:31
DSL Type:	G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:	1,211 / 8,133
Data Transferred (Sent/Received) [kB/kB]:	0.00 / 0.00
Output Power (Up/Down) [dBm]:	12.0 / 19.5
Line Attenuation (Up/Down) [dB]:	13.5 / 24.0
SN Margin (Up/Down) [dB]:	7.0 / 14.0
Vendor ID (Local/Remote):	TMMB / BDCM
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):	0 / 0
HEC Errors (Up/Down):	0 / 0