those are extremely high ping times m8
200ms is back to 56k telephone modem speeds - so 2000+ there is defo something wrong.
ur modem is good m8 - one of the newer surf boards - and its black
should have no problems with 4mb.
do all the recommended clean outs - and follow some of the previous thread info on configuration page of ur modem.
2000 ms is scarey tho - get on to tech support directly too.
best of luck.
ps - just a hunch - but next time u take a ping test/traceroute etc. note the times.
ive been researching BY's high pings of late - and there seems to be more than a few "pockets" of rubbish service at peak times 6-11pm appearing over the country - with no better response from telewest than giving the few that dont take their waffle of cleaning out spyware etc -giving them reduced cable fees.