In reality the ICT Co-ord deals with the teaching aspects of IT and as a member of SMT is 'responsible' for the IT budget. In reality I have almost complete control of IT procurement and management. He just signs the order forms that involve his budget.
Once a year I put my development plan to the SMT and they agree a budget with the Governing body and decide what they would like to see over the next 12 months.
At the moment it works well and I keep control of what goes on.