Business Plan for an Innovative Consultancy

We're starting up a consultancy business because we can see (and are starting to capitalise) on white space opportunity in the market. We have no documented business plan but a lot of the details are in the owner's head. We need a way of qualifying and capitalising on the opportunity properly so we can deciding how much to invest and where to invest. We also need a way of managing progress towards some kind of objective or vision. A business plan would seem to be a good way of doing this, but we have limited time to prepare this as we're all working on capitalising on the opportunities we're facing.

The work is likely to be iterative - the first phase will be to create the key parts of a business plan, identify further gaps that need to be filled and to to prepare a plan to complete the plan. Hence the timescales are indicative. We'd also prefer to work with someone whose based in London (so we can meet) and who has a reasonable understanding of the tech market in the UK.