@spinningfish I've had a look and it seems to me that the appeal could have been won, but I don't see that the adjudicator has made any obvious error.
The argument that should have been pursued is that, in the absence of the broad yellow line, there was nothing to put a blue badge holder on notice that it was necessary to check the upright sign, so the overall signage was inadequate within the meaning of regulation 18 of The Local Authorities' Traffic Orders (Procedure) (England and Wales) Regulations 1996.
I can't see any scope for a review because ultimately you're not entitled to a second bite at the cherry, the argument should have been put forward the first time round.
The only thing I can say is that if you're ever in this position again please PM me
before the hearing, this is the sort of case where having a professional representative could have made all the difference.