Quick correction
Both TalkTalk Technology and Vodafone use Dynamic Line Management on their LLU platforms, not just BTW. The protocols are different, with different levels of sophistication. TalkTalk and Vodafone will only manage line rate at the DSL layer, whereas BT then match that with management at the IP layer too.
The upshot is that on BTW if you replace a crappy filter your line rate will go up fairly quickly, but your actual speed (IP Profile) will lag up to 2 weeks behind unless you go through painful support processes. On the other networks, changes to DSL rate are instantly reflected in throughput.