Where is Rupert Degas ???

I am referring specifically to the unabridged audiobook version English, so nothing about the story itself.
One of the main reasons that I had so much pleasure in skulduggery, was the brilliant reading performance by Rupert Degas. Since the first four volumes read by Rupert Degas, I assumed, as was to be found otherwise in the item description that also Mortal Coil is read by him.
This is unfortunately not the case.
Brian Bowles makes his job well, no question, but to my ears it does not reach Rupert Degas. I was also missing recognition effect of the individual characters, as Brian Bowles them differently (just in his own way) works out with its tuner.
Overall, I love Brian Bowles fun, fine elaboration of accents and different ways of speaking of the characters, slowly and clearly enough for non-native speakers.

Addendum: At the second hearing me Brian Bowles like getting better, he works much more subtle with his voice as Rupert Degas.