LLU has been pretty much been a joke for reasons stated. BT needs to be given the capital from central funding to upgrade the infrastructure to suit 21st C demands irrespective of who provides the ongoing service. it's akin to upgrading the rail service - without the capital investment in upgrades it will never improve or at a rate that is so tedious it makes it a joke.
the UK has been under-capitalising major infrastructure projects for years - hence why we have no decent high speed train services, a poor telecoms network, a useless national water pipeline to get water where it's needed, etc etc etc
it's one of the reasons I am coming back around to nationalisation as a way forward to these things and get rid of the myriad of companies who are only interested in their shareholder returns.