the reset problem when trying to access the adsl stats on the HH2b is known and bt are supposed to be working on it but with it being replaced with the HH3 I wouldn't hold your breath.
please can you post the adsl stats from your router may need to 'show detail' to get all stats (if hub enter 192.168.1.254 in your browser and navigate to adsl or use a-z, if netgear enter 192.168.0.1) and run btspeedtester http://speedtester.bt.com and post the results.
Someone may then be able to offer help/assistance/suggestions to your problem
your noise margin is high at 14 as normal about 6 probably due to the disconnections when accessing the adsl stats. have you had other resets apart from when you access the adsl stats? can you manage to run btspeedtester and post the results?
you have a 3mb connection but without the btspeedtester results cannot tell whether your profile is low due to the resets or if your throughput is low or both.
if your line is stable then you can contact the mods to get changed back to fast - fill out the form http://bt.custhelp.com/app/contact_email/c/4951
the mods can take a few days to get back to you - sounds like you have a congestion problem in the evenings