That firm is either deliberately telling lies or they really don't know the rip-off prices they are charging their customers to contact them.
There is no such thing as 'long distance' or 'local' any more and certainly not in relation to 0870 numbers. In fact, that was one of the original purposes of 0870/0845 numbers - whatever the distance, the call charge per minute is the same. However, that 'argument' has not been valid since 1/7/04 when BT introduced its standard UK-wide weekday daytime rate of 3p per minute for calls to all 01/02 STD codes.
BT's charges to call 0870 numbers do, however, vary according to day/time of day:
0600-1800 Mon-Fri 7.51p per minute
1800-0600 Mon-Fri 3.75p per minute
All day at weekends 1.5p per minute
Others charge diferently.
OneTel, for example, charge
8p per minute at all times for most 0870 calls and
call18866.co.uk charge
9p per minute at all times.