you can't base return on investment on turnover - grum may have been nearer the truth imo.
£80 odd Million (allegedly) over 4 years means you must expect £20 million
profit a year to break even.
If you have to install hardware to get it to work without impact on the existing "network" it becomes even more bizarre from a short term economic perspective? (ubr allegedly = £30,000 ?)
Could we be seeing a long term plan to use the good bits of the cable network in a beneficial way? (apart from AOL's browser, of course - imo

)
Or, more cynical, an attempt by ntl for some investment and "hang the consequences"?
Or, a "rumoured" takeover?