Just pausing this, as I'm not sure if John as administrator has been made aware of this. Not saying it won't go ahead - I just need to check. Hope you'll bear with me.
Interesting and nice idea. Appreciate the giveback element however would rather see the 50% you don't propose keeping go either to charity or the retrobike club.
Could all be a moot point anyhow, have read the guidance here 'Lotteries and the Law' and as far as I can interpret things without seeking some sort of permission this is indeed illegal. Sorry for being a Buzz Funkill. If KonaJJ (or anyone else) has any suggestion please PM me.