Redevelopment of an 'end of life' building

Hi all, here at my authority we have a civic building which could be described as 'end of life' in that it is in a state of poor repair, dated, has mounting repair costs etc. The Council has an interest in conducting a procurement exercise to secure a developer that will not only pull the civic facility back from the brink but also develop a wider connected building complex that may involve supporting small business, supporting the community and generally acting as a regeneration catalyst for the area in which it sits. Has anyone been through such a process within the UK before, if so which providers did it identify. Also if you were in a position where the development requirement could not be tightly specified then what process was utilised to procure the developer, i.e. was it Competitive Dialogue, or Competitive Process with Negotiation? Any experience's that you can share would be greatly appreciated. Cheers,