As well as the useful document published by the Contact Council, referred to previously, Mr Lowe may be interested to refresh his understanding of Ofcom advice by referring to the following:
Number Translation Services (NTS) including 0870: FAQs - notably question 6 (some of this is now out of date).
Ofcom introduces UK-wide 03 numbers - a full description of the 03 range, from when it was launched.
The 03 alternative - addressing the change that organisations now need to make.
All of these documents may be recommended as valuable reading for any public sector body using revenue sharing numbers.
It could be worthwhile to challenge the need for non-geographic numbers, to confirm that it is not simply to gain the subsidy provided by the revenue share.
The difference in cost between a 0844 and 03 number is the amount of subsidy that callers are providing. (Notwithstanding profiteering by telephone service providers.)