@oxygene can you confirm if there is any other advice you need from members before I bring this thread to a timely close? I feel it has served it's purpose now, neither party believes they are at fault, any number of posts or opinions aren't going to change that fact. There are 2 courses of action, take it on the chin as a life lesson and move on or take it court to plead your case. James is no longer on the forum, so there is nothing that the club can do about this, it's just going round in circles.
I'd take this time to make an important note, this club is a community of enthusiasts, the club facilitate that community by arranging events and hosting this online forum. We do not recommend or endorse any hobbyists or traders, that is done by our members in a democratic way. The club is not a shop, auction house or trader, we are not affiliated in any way with our traders and have no vested interest in them. If on the rare occasion there is a disagreement, we facilitate an open two way conversation to help reach a resolution. We are not a legal body or legal practitioner and as such, have no legal powers should you not be able to reach a mutual agreement. At this point you will need to take advice from appropriate sources to decide a course of action, which may or may not be court.
Ultimately, any services/parts/sales are done at your own risk, it is your responsibility to do your due diligence and protect yourself as much reasonably practicable.