Ahh! Silly of me. I was unchecking ‘replicates’ instead of ‘replicates movement’. Rookie error!
I do still notice some jittery movement for other clients who are with me on my boat/moving platform. I tried increasing the send rate for players and the boat to 60 but that doesn’t seem to have any impact sadly. I also have ‘scale’ set to NONE, but perhaps that is unnecessary (it doesn’t seem to be causing the issue anyway). They are all clients, currently running this using “Play As Client”.
Thanks again for the support 