It's been a while since I've seen a yellow pages - I haven't got one.
For those that have got one then I do believe it helps our cause to complain to Yellow Pages (at first) and pointing out to them that 0845 isn't local rate and pointing out that ASA guidelines stipulate that call prices have to be displayed (include links to appropriate ASA guidelines).
I can only guess that yellow pages would probably inform their customers that their adverts that have an 084/087x in them have to mention the call costs.
This, I hope, will then maybe force companies that have 084x/087x numbers to maybe switch to their geographicals. This is more likely the case for those companies that have 0845 and therefore are less likely to earn a revenue and were probably missold their 0845 on the basis that it is cheaper regardless of where their customers are calling from in the country. This is especially true for companies that do not need advanced calling features offered by 0845 (eg smaller companies) but only got them because they were misinformed about 0845. Of course those companies that operate more than one call centre across the country do unfortunately take advantage of advanced calling features.
Those using 0870 are likely to be earning a revenue so therefore are less likely to switch back to geographicals.
I'm hoping that these smaller companies that were misinformed about 0845 will realise that they are not helping their customers by operating an 0845 especially if the company concerned has to start mentioning the costs of calling 0845. This is more true if the company concerned is informed that 0845 isn't local rate which they will only believe when the likes of the ASA inform them.
As we know, companies don't generally believe us when we say that 084x isn't local rate and 087x isn't national rate simply because for years they have been known as this and many companies (including to a certain degree BT) still maintain this scam.
The two relevant links about ASA guidelines concerning these numbers are
here and
here.