I now know the answer.
1/ Prepare something to eat, then sit down and begin to eat, the phone will ring!
2/ Go to the toilet for a no2 without your mobile, it will ring!!
3/ Have your mobile with you all day without a call, forget to pick it up from your van for about 5 mins. You will have 68 missed calls and 5 messages.
4/ Go on holiday for a week, your phone will never stop ringing until you return.
5/ Go out for a meal at about 9pm on a Friday evening, there will always be a message waiting on your return!!
Right I'm off for a poo, need the phone to ring!!

Peter