Crowd funding sounds a bit involved for £4k, without knowing anything more than the contents of this thread, would an interest free credit card be an option. This is how I managed to fund my track bike, Santander 18 months interest free on all new purchases. Just needed a plan, bought everything on the card I could then put the cash to one side. I would imagine your suppliers will accept payment by card and you get an interest free loan which you control to suit your cash flow. At worst you can get a balance transfer near the end of the period to switch to another card, just never forget to pay the minimum..
Just a thought.
