LLU will just mean you're connected to a different DSLAM at the exchange, possibly with a different firmware level and chipset, which is interacting more favourably with your modem than the BT fujitsu kit.
Trust me re Infinity, since it was supposed to be made live here in Dec 2010, then March 2011, then Dec 2011, then March 2012, then Dec 2012, i'm holding out not much hope of it ever being here by the time I move house anyway! However, whilst i'm apparently 2.6km from the exchange as the crow flies, but 9.1km from it as the whoosh test proved the cable runs, and i'm only a few hundred metres away from a roadside cab, i'm seeing it as the only way to get semi-decent broadband in the technological wilderness that is Bracknell (ahem).