Some of the (old) information can be gleaned from these:
http://usergroup.plus.net/report_pncapacity.php
http://usergroup.plus.net/capacity_calc.php
Some of those old Plusnet pages show their age.
Not surprising. I wrote those over 10 years ago.
It caused quite a stir in its time because it was actually an in depth representation of how much it actually cost the ISP and something no-one had been able to do before. I was in a unique position to be able to get quite accurate information and data over a period of time and it took a long time (months) to write. I dont think the ex-CEO was too happy about it initially, but realised if I didnt run it on PUG it would go elsewhere
As it turned out it was actually received favourably by both EUs, other broadband sites and some tech articles & journals (such as Computer Active who covered it) because it helped people understand where their money went.
If it was done today, the pricing would be cheaper:-
1) At that time MST had recently been introduced by OFCOM and BT backhaul costs were kept high due to the OFCOM ruling trying to promote LLU. There were very, very few Market 3 exchanges so predominately everything PN sold was Market 1 and perhaps one fifth Market 2. Neither of these qualified for deregulated pricing. By nature of the beast Market 3 exchanges already were automatically those where cable had an excellent footing.
2) Since then, BTw has upgraded to 21CN, which in itself has brought cheaper backhaul costs. WBC is more efficient to SPs than the old datastream which never really worked. 21CN offered SPs more choice of where they entered the network.
3) DSL has a much larger audience. The more EU's an SP has, then the more efficient CBC pricing is.