This morning I received the Nauticam production model fibre optic strobe trigger. Thanks Alex!
For the past few months I've been using the prototype Nauticam trigger which proved to be unreliable when shooting with YS-250s. Z-240s were OK.
The production trigger seems to have resolved this reliability issue with the YS-250s and topside I just shot off 40 or 50 frames and successful triggers with connections made at either sync sockets on the strobes. I'll take my NA-5D3 and YS-250s to depth next week and will report back on the outcome.