There is a course run by the British Helicopter Association (formerly the BHAB)to help to make commercial pilots suitable to act as a Chief Pilot. I think this runs for a week or so, but you should check.
However, you need to be a commercial helicopter pilot to do that course.
I don't think it is "do a certain course" which then guarantees the CAA will accept you. They look at past experience and knowledge - and from what you say you have very little.
In practice more than one person will be required to fulfil all the postholder roles required for an AOC. I am sure that the CAA will look at the qualifications and expereience of ALL those nominated postholders in determining acceptability.
There are no short cuts. If you want to take on the role you suggest, you will need to be familiar with the regulations themselves and CAA advice on setting up an AOC. Once you have read those you will have a much better idea of what is involved - a LOT of work and a massive admin burden AND a rapidly increasing membership fee - curtesy of new CAA proposals on charges.
My advice - do whatever it is you want to do some other way than having an AOC.