At some point in this preparation stage you need to think about the practicalities of brand-building and implementation.
Think about your in-house resource. How much of this can you do yourselves and how much of it will you need to outsource?
You may feel that you can handle the research phase in-house but that you need some help with writing the narrative. Your in-house design team or the existing agencies on your framework may be able to produce the high-quality creative you will need. However, you may need to buy in specialist support. It is worth doing an in-house skills audit at this stage, and thinking about key businesses in the area that might be able to help with aspects of the work on a pro bono or reduced rate.
Remember to talk to other councils who have done good work in this area. Some may be able to share work with you, recommend contractors or even carry out some aspects of the work for you on a contracted basis. This is likely to be cheaper than using a commercial agency.