Hi and welcome to SAYNOTO0870.COM.
Abbey is evidently trying to mirror its sister company, Alliance & Leicester (more on A&L customers who have been "banned" from calling non-premium numbers
here).
When you call the 01908 number, make sure you withhold your number, although there's no guarantee that that will have any effect.
From 1 August the process that supported revenue sharing on 0870 numbers was scrapped. BT and some other providers have reacted by bringing their 0870 prices into line with 01/02/03 calls, although notably Virgin Media and the mobile operators have not.
You ask whether companies on 0845 numbers are obtaining money, but that's not the real point. Regardless of whether they revenue share directly with their telephone provider, they are benefitting through subsidy from callers. This happens in all cases, regardless of whether the caller is on an inclusive tariff or not.
For this reason, if they wish to operate a non-geographical number, they should switch to a 03xx one. These are are cost-neutral, that is they are priced inline with geographical calls for everyone.