Scott, if Grant has made the transaction on the price you have stated on your web-site, under consumer law is he not entitled to the goods at the price advertised?
It's your mistake.
There is a "report" function to send your feelings to the moderating team but I am unaware if the bug in the new software has been rectified. Otherwise send an e-mail to phil@sidc.co.uk
I'm sure Phil will happily convince you that advertising on the SIDC forums is a worthwhile investment for your company.
Regards
Dougster