There is nobody in that area that I could or would recommend for work on a Purdey, especially when it's an issue with WEM ejectors. You are going to have to send it out for repair. You have really good options in Oklahoma, Texas, Utah and a few on the east coast.
And what's up with the barrel bead? You didn't pick the size you wanted before you had it installed? Easy enough fix I suppose...unless the recent install involved over sized hole and a re-tap. If so, price goes up.