Two options:
1. You make it yourself. Some tips in https://www.gov.uk/write-business-plan or http://www.sba.gov/tools/business-plan/1
2. You pay a company or freelancer to make it for you. Just a random google hit (not meant as recommendation): www.ogscapital.com/services/business-plans
For #2 it's best to find a local company, because you will have to talk to them about your plans and ideas.
Jees
Hi, please advise me where I can order some business plan for my idea?
Chowhound
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