If you were thinking of running it as a non equity group you will have to run it on the EASA equivalent of Public Transport C of A. The same goes if you want to run it at a group where people have shares of less than 5%.
Pvt CofA and Permit means that everyone needs to have at least a 5% stake in the machine. If you have £1k shares that would mean a capital of only £8k; you are unlikely to buy anything particularly useful in the SEP class for that sort of money!
If you need to borrow the money and do something like that the lender may want to see some kind of business plan (unless you can easily service the loan from your own income without requiring any 'income' from the venture)
As is mentioned in the other post, try to find likeminded people. If your group consists of those that like to fettle the bird endlessly and do little more than have an hour every 2 weeks in the local area an hourbuilder or someone who wants to take the machine away for long trips abroad will upset the applecart!
If your main objective is to build hours and you have not identified a few likeminded folks you could do worse than trying to buy hours off someone that has an underutilised aeroplane gathering dust or approach a school to buy some serious blocks. Especially at this time of the year there may well be a few that would welcome some cashflow.
Identify what your main objective is and act accordingly.