You're referring to these?
https://www.ebay.co.uk/itm/SP13-SP17-Std-Series-IP68-Waterproof-Circular-Multipole-Plug-Socket-Connectors/161568085294?_trksid=p2485497.m4902.l9144
Looks like a good option, thanks. Just wish I could find them at a better price.