Robin
I have sympathy for your you but your CAMO also has the probelm that if is fails to meet the requirments of part M and the authoritys pick this up they will get the approval pulled and instantly have no business.
The trouble with your Propeller is not a Part M issue even under the BCAR system the prop would have needed a Form 1 or FAA 8130.
In a recent audit we have rasied some issues with the CAA and made it clear that we suspect (but cant prove) that the part M system is resulting in "underground maintenence" being carried out.
We are also have contacted the CAA CSO about a number of issues arising from the requirments for a Form 1 when parts are removed from one aircraft and fitted to another if full tracability is not an issue, we are also working on the full scope of GR24.
On a personal note we do a lot of Robin work and if yours is wooden we might be able to help you.