Hi there, I work for Orange and might be able to help.
temoore is correct. I have double checked the info we have for the Bold and it suggests-
Line One: **61*Divert No.*11*N#, Send/Call.
Couple of things to note - the divert number would be 07973100123 and it is up to 20 seconds, therefore you would enter-
**61*07973100123*11*20#, then press the Send/Call button
Hope this helps,
Orange Response Team