Here’s an excerpt of an interview he did in 2001 with Sound On Sound
For example, when I was working with Andy Wright on the Eurythmics album Peace, both he and Dave Stewart had put ideas into the demos from which I was working. These I worked into the score, and also some of my own ideas. In the old days you were given much more of a free hand in this respect — one would be working with already accepted songs, and you’d be expected to give them a new and different treatment, which gave you a lot of licence to do your own thing. In a way, it is nice that songwriters now remove much of the need for the arranger to summon ideas from thin air, though this is something I’ve always been perfectly capable of doing. It’s just that bringing in new ideas takes more time and more effort.
Read more about David Whitaker here.