08 numbers are "nongeographic" meaning that they are not associated with a particular area or town. Originally they had some advantages but in the modern age of flat rate landlines and mobile phones they are no longer fit for purpose. If you go to the saynoto0870 web site you may be able to find an alternate geographic number.
Basic breakdown of the types are;
0800 Freephone Free from landlines but can be expensive from mobiles
0843, 0844 and 0845 Originally local rate from landlines but now that there is no distinction between local and long distance the ASA has banned them from being advertised as such. Cost varies from 5p to 41p per minute depending on carrier.
0870 and 0890 Premium rate that can cost several pounds per minute often used for sex lines.
