You have a very nice idea but I have spotted a few things that seem wrong in my opinion. Keep in mind this is what I think..I am not saying that this is what you are doing but people may assume this.
- You say it is transparent so that the owners cant just run away with it. Even though it is transparent they can still run away...
- Offshore and US IP - You will get into some serious trouble even if you hide yourself etc. They will still find you.
- You said you needed at least £2,500 to run this operation.
- You are 16.
- You are too new to announce something like this.
[.] You are asking for money (investment) into your project with no proof of guarantee and or collaboration for it
[..]
"Work on this all summer" - Trust me a project like this will take a lot longer. If not expect to get a lot of negative feedback as you are not a actual team of developers. From what I see you are only doing mock ups. Something like this would take at least 1-2 years of building and a good few months of bug testing.
[...]
"buy the things I’ll need (e.g. Balsamiq, Sublime Text, ...)" - Balsamiq is just a mockup application which people commonly use to make interfaces to make fake projects and get people to invest and run from them. Sublime Text works just fine with the free version. It seems like you are just asking for money to buy things that are not even needed and does not help this at all.
[....]
"contract a developer for a few hours if needed + get some professional regulatory advice" - With a £2,500 budget you won't get this project finished and that you are looking for developers means you actually have no POC yet but just a mockup which doesn't do anything if you have not had a team working on it yet. Also that budget won't get you the experienced people needed to make your project except freelancers who lie their skills or just scamlancers.