Dificulty Calling 07031 Number from UK Landlines and Mobiles

I use a voipuser 07031 number to redirect to my O2 mobile during the day and my voipuser sip during the evenings and weekends.

I have over the last few months had a number of people email me saying that they tried to ring me but the number was barred from their phone. If I call it from a friends mobile it works frin but it I call it from my office I get a voice message saying I have tried to ring a premium rate number and that it is barred. I assume that this is due to the high call charges.

I wondered if you were planning on getting some 07xx numbers that could be redirected to UK mobiles that can be charged at more normal mobile rates?