That sounds like the shoot I did my apprenticeship on in Worcestershire years ago, structured and effective vermin control, habitat management and wild grey partridges. It is perfectly possible to create a good shoot so long as you have suitable ground Matthew, it just needs hard work and dedication to make it work. If all 3000 acres of ground are suitable, and the neighbours are also on side, then there is no reason why you could not expect to have 300 breeding pairs in that time frame.
I hope you find an enthusiastic young 'keeper to make a good go of it - if I was available then I would