Aside from being a 'Nav', I always thought VCDS was an up or out type appointment. In any case, a lot will depend how he does politically - at that rarified level performance is often judged by how you handle yourself amongst the Westminster bearpit above and beyond other performance metrics.
Plus I'm not sure it is the right time for another RAF CDS. The Army have double tapped the job on the grounds of fighting a ground-centric campaign and before that we had Jock Stirrup. Whilst not entirely in the spirit of the being the right person rather than buggins turn, I suspect the RN might be angling for it when Houghton leaves - although my knowledge of RN VSOs and their position in the pecking order on the Defence Board is sketchy.
Plus, as he has already held 4-star command as Comd JFC, I'm sure there would be others working their way up through the system that would be a little miffed if Peach got a 'second bite' so to speak.