It is up to you. Your chosen IP will be informing them as well. If you do any online banking - go in and remove your contact details so they can't phone you.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
I did write letters to each of the providers whilst my IVA was being drafted as I had been advised to make token payments to them and I knew it wouldn't cover the minimum. I used a standard template explaining how much I would pay and the date I would pay it. I also stated I would only deal with them in writing not on the phone. I had the most overwhelming sense of calm as I stuck those letters in the postbox. Now I look back and wish I hadn't paid them anything and built up a bit of an emergency pot, but I was so worried they would vote no!
As Kallis suggested removing your phone number is a good idea, I didn't but I did set my phone to reject all withheld calls automatically. I let Leeds numbers go to voicemail as I wasn't sure if they were stepchange or first direct. They were all first direct!