Ownership dispute

[Rustymetal]

I loaned a mechanical part to a acquaintance 'A' who was restoring a small railway locomotive, the agreement was that I would receive a similar part in exchange on project completion. Person 'A' decided to sell the project to person 'B' before completion and included my shaft. I contacted person 'B' and explained the situation and they agreed that I should have the part back. 'B' then exchanged the part for another part with person 'C' forgetting our agreement. On realizing his mistake 'B' offered to reverse the swap but 'C' is refusing has he says he performed the swap in good faith and considered the part as his property. How do I stand legally as there is nothing in writing?

[Amethyst]

Re: Ownership dispute

Your issue is with person A - who had the part on agreement he'd give you a similar part on completion of the project. Sale of the project could be classed as completion ( he has completed his bit) so should give you the similar part. ?