So this is purely my fault so i'm to blame here.
Yesterday I spent a good few hours mucking about with my Vigor 130 and during those times when changing settings its asked to be rebooted. I suspect that those reboots have caused my line to become interleaved and also a drop in speed. P.S I would like to add I did decided to try the SNR trick yesterday (which saw increased download speeds) and it didn't cause significant errors on my line so I don't think thats relevant but just as a precaution I removed any modified settings and put them back to defaults.
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 61358000 bps US Actual Rate : 19993000 bps
DS Attainable Rate : 71631752 bps US Attainable Rate : 20890197 bps
DS Path Mode : Interleave US Path Mode : Interleave
DS Interleave Depth : 895 US Interleave Depth : 253
NE Current Attenuation : 12 dB Cur SNR Margin : 6 dB
DS actual PSD : 3. 1 dB US actual PSD : 3. 3 dB
NE CRC Count : 0 FE CRC Count : 2263
NE ES Count : 0 FE ES Count : 1895
Xdsl Reset Times : 0 Xdsl Link Times : 5
ITU Version[0] : fe004452 ITU Version[1] : 41590000
VDSL Firmware Version : 05-07-09-0F-01-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 12 dB Far SNR Margin : 6 dB
CO ITU Version[0] : b5004946 CO ITU Version[1] : 544eb206
DSLAM CHIPSET VENDOR : < IFTN >
>
Looking at this, interleave depth isn't too high... so fingers crossed?