This was a non-functional prototype, however it proved a number of aspects of the design. In particular, the compliant spring design appears to have worked.
Many thanks
communication was great but they had to reprint the order as the first run was bad quality, which took an extra week, but they used next day delivery so I did get it straight away
I received my 2 3D printed parts to my own design with helpful communications from the supplier. Great service and first-time experience in 3D printing services. Many thanks. CW