any tips on low voltage 3 conductor connectors, good for outdoors?

Other Hardware General Electronics
15

6v6gt:
Maybe:

https://www.amazon.co.uk/Pisces-IP68-Waterproof-Cable-Connector/dp/B00BKY6OZA

I found it by searching for “garden pond electrical connections” and looking at the images!

Thanks, but its not a panel mount type.