I put in a disclaimer on that, in general, my understanding is they will put you onto the BT system unless LLU is available, whereby it varies. In general for the majority of people that's BT though.
Ergo, 8Mb can be LLU/BT, whereas 16Mb will only ever be LLU atm. Hope that makes sense, I was commenting on Kree's comment that 8MB would be LLU, whereupon it actually varies, and a lot of people would find themselves with an over subscribed (and this comes from an internal UKOnline memo!) BT service, which they don't intend to improve. From what I've seen at samknows, whilst LLU coverage is growing, its still less than half the exchanges in the UK.
To clarify, UKonline CC is pretty decent, 12m contracts are nasty, LLU is meant to be very good, but thier BT product; which is a large percentage of up to 8Mb users, is pretty poor.