Ask an Property Solicitor. Get an Answer ASAP.
My name is ***** ***** I have been asked to help. You do not have the right to retain the machinery which you know not to be yours. It could arguably be considered theft and they could involve the police. That does not mean that they should not be carrying out the terms of the agreement. I would be minded to get a solicitor to write to them formally (threatening court action) if they do not confirm that they will abide by the terms of the agreement or in any event they can not continue to have access to your property and that will sue them for recompense. Happy to discuss and please rate 5 stars for my time.