Have you tried asking them to optimism your connection for ping, I did that with sky and it dropped my ping from 80-90ms to 20-30ms. But I think you need a tech support fella who actually knows what ping is and they are in short supply.
This applys for ADSL connections only, it's just disabling Interleaving. I'm tempted to do it on my connection as my latency is rubbish (minimum 50ms), but as i only get 3Mb I'm loath to sacrifice sync speed.
Can't really help I'm afraid, when I had Virgin 10Mb it was rock solid, ~10ms pings 24/7 and speeds never dropped.
Well I'm on 50mb/s here, should technically be uber. Sadly....
EDIT: Just ran a speedtest here...

I have no idea, I doubt it will be this good tomorow. How has it gone from so shit to this?