NIGHTMARE

I have just been informed by the machine shop that though the crank has been ground before to 0.25. The crank grinding company states that them cant grind the crank again because of the application.
I have mentioned that cosworth cranks can go to 0.50 and still be safe but the company doesn't advise that. When I speak to other machine shops and mention the crank grinding company they all say there the best at what they do and take there advise.

So, does anyone have a Cosworth crank for sale which is crack free, straight and stock or advise me on any other options

Thanks
Andrew