I just wanted to chime in and say that Peco could not have been more helpful on this front.
One of the crank pins on my Prince came loose and pinged off into the ether. I emailed Peco that evening and the spare pins were in the post the next morning.
They arrived half an hour ago. I’d grabbed some tweezers and a cup of tea and prepared for a fiddly job, but they come attached to a sprue, making it a simple matter of lining up the holes, pressing the pin home, and snapping off the sprue. Less than two minutes and Prince is happily running again.