A couple of calls to BT later and with the speed down again to 104 kbps. (but 386 kbps. upload).....I`m now told it can`t be fixed 'remotely', so a lineman will come to Deb`s towers on the 21st.; he must be walking all the way from Bangalore! 
BT`s own speedtester shows the IP profile to be 135 kbps. but shows the 'line configuration' to be the same as the router stats as below (2112/448)......but does it look like a physical line fault?....I wonder why a simple 'reprofile' can`t improve the BRAS :-/
Modem Status 
 Connection Status   Connected 
Us Rate (Kbps)   448 
Ds Rate (Kbps)   2112 
US Margin   17 
DS Margin   9 
Trained Modulation   GDMT  
LOS Errors   0 
DS Line Attenuation   59 
US Line Attenuation   31 
Peak Cell Rate   1056 cells per sec 
CRC Rx Fast   0 
CRC Tx Fast   0 
CRC Rx Interleaved   7 
CRC Tx Interleaved   0 
Path Mode   Interleaved 
 
 
DSL Statistics 
 Near End F4 Loop Back Count   0 
Near End F5 Loop Back Count   0 
 
SNR on downstream looks low. Given the high attenuation, the BRAS does look optimistic. The BRAS should be dynamic...
I don't think the ISP have much input into the BRAS - they have to send to BT Wholesale via ECO to have alterations I believe.
Shame you can't get the line test results - trouble is, the LTS tries to guess the fault (some are better than others, and I don't know which one is used in North Wales) based on lookup tables, but a trained human eye can often inteperate them better - bit like an engine ECU, dafts technicians read the codes and change parts, rather than inteperate them.