Welcome safron,
Generally it's better to search for alternative geographical numbers by company name rather than 084x/087x number.
As well as the link provided by Heinz, there are a few others you may want to check out like:-
General Info about posting & requesting assistance finding a geographical numberGuide to finding geographical numbers (as posted by Heinz)
Feel free to read some posts and any stickies (under the heading Important Topics).
Another site (in case you're not already aware) is Money Saving Expert (aka MSE) which actually sponsors this site. Over at
MSE, they discuss more ways of saving money and not just by ringing geographicals instead of 08x numbers. Things like credit cards, utility bills, insurance, etc are discussed.
If you do, unfortunately, have to ring an 08x number then check out MSE's
Call Checker.
If you have any queries then let us know.