Fuel filler confusion

[Bonzo]

Before I fully commit to the fuel filler I can give some thought to the following options.

Contact my local IVA inspecor for guidance, he did say not to hesitate to contact him during the build.

Bite the bullet and splash out on an aerocap, yes they do look the muts nuts

Go the lo-cost route & scavange some suitable parts from the breakers.
Thinking....Filler flap hiding a filler point, this could be made lockable with one of those small electric servos that so many filler flaps tend to have.
I am aware that if the filler cap is not lockable then it must be tethered