this is a permitted use of 08 numbers - the price you are paying is directly paying for the calls you are making.

If you really want cheap calls to Asia, then you may be better off looking at alternate ways of calling them.  There are lots of VoIP providers, for instance, that offer free calls to various countries in the region. See here for a comparison of the various betamax brands, for instance.  (And remember, with a simple 'ATA' adapter you just plug between your phone and phoneline and connect to your internet, you can divert calls via VoIP automatically.)