I too have Orange UK and was finding my calls got sent to answerphone before I had a chance to answer. Phoned up Orange support and the guy there told me how to change the time before the answerphone cuts in.
You dial **61*07973100123*11*??# on your phone dialer and then hit the call button. Then hit the OK button on the message that comes up a few seconds later.
The ?? represents the time in seconds you want to set before the answerphone kicks in. There is no point in setting anything longer that 20 seconds, because that is the maximimum - I have tried it with 30 and 40 and with both the answerphone kicks in after 20 seconds.
Be careful when dialing the first two "*", if you press too quickly you end up with a "p", so leave a couple of seconds between them. AFAIK
this tip only works on Orange UK.