I don't want to break your heart here but from a 'Dragons Den' point of view you've already told me that you don't have a large network of contacts and that you don't know how to set up your own business.
As such I think it's probably not the best step for you at this point - and mark those last three words.
Why do you wish to set up on your own? You either have to be providing a new product or providing an existing product cheaper or faster than your competitors.
Who are your competitors? What are their strengths? How well known is their brand?
How do you differentiate from them? Why would your customers buy from you?
Who are your customers? What do they want? How happy are they with their options in the market now?
If you don't know the answers to these questions you are working on desire rather than a plan. If you don't have a business plan which has been tested you have a dream.
Now to pick you up. You appear to have fantastic experience, your problem is that it's all been internal so your network and profile is low.
My advice would be to lever your experience and move into consultancy. Spend 2 - 5 years building your network and profile amongst buyers in your market and then, if you can answer the questions above with confidence, make the leap.
Alternatively look at the contractors area of this site and see if this is a way you could get into freelance work.
Either way, people will know you, they will trust you, they will believe in your brand.