Rule 7 is a little vague, I do need to ammend it, not sure how we can prove intention to sell
I have been head admin of a forum myself, so I know how difficult it is to make foolproof rules.
My suggestion would be to change the wording of that rule.
"Intention to sell" is difficult to prove, unless there is evidence to be found in the forum that the bike is for sale. For instance: a topic in the sales section, the owner mentioning anywhere in the forum that the bike is for sale, etc.
That last example is still questionable though, as there is a difference between "mentioning that you are thinking about selling the bike" and "looking for a buyer".
Judging by the "SOLD. Cheers, Sean" quote, it is clear that the owner is not only looking for a buyer, but has already found one and that partial arrangements have been made.
No matter how vague "intention to sell" may be, to me it is obvious that this bike is being sold. Maybe the transfer will only happen in november, but that doesn't change the fact that the owner currently is involved in a sale of that bike.
IMO that's the difficult bit of this particular case. It may still be in the owner's hands right now and may remain so for the rest of the competition, but it's a grey area indeed.
Wether you accept the submission of the bike in BotM or not, is at your discretion. I really doubt that people will start protesting if you make a call.
TBH I doubt it'll get any votes with a picture that was obviously photoshopped, and especially not after this whole discussion. It certainly wouldn't get mine.