I can assure you that Emma Holmes is completely real - she and I used to work together a long time ago! I suspect that you are getting pp'd letters, as McCambridge Duffy have grown into a large processing firm, and she cannot possibly deal with all of her clients personally.
McCambridge Duffy are not linked to Max Recovery, who are a firm of debt purchasers.
If you have not yet agreed to enter into an IVA, there is nothing to stop you changing providers. The basis of the IP's fees should have been discussed with you from the outset - surely they have sent you an engagement letter which you were asked to sign as part of your agreement?
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk