My first attempt was a month ago at Shelly Beach (near Manly). Conditions (for photography) were really poor due to the swell. While it was not at all rough at Shelly, it was rough around the corner and that was bringing dirty water around and there were just too many particles in the water. (The strobes light up any particles and you get awful back scatter.) I didn't even get one decent photo the whole dive.
My second (and third) attempt was last Saturday at Magic Point (off Maroubra). There's a cave with grey nurse sharks so this was going to be a perfect opportunity. I tested the rig before I left home (as I always do) and everything was working fine. After my first test shot in the water I discover that the strobes aren't going to fire



I did try a few shots with available light but the sharks were just too deep (14m) and there's no colour:

I have one semi-reasonable shot:

but it is more of a snapshot because I was trying to get the strobes working rather than concentrating on framing.
I tested the dual sync cord (drives 2 strobes) when I got home and it appears there's a break somewhere along it and it only contacts some times. I'm not sure if it can be repaired or I'll have to buy another one (@ US$152 plus shipping). I am fortunate in that I have a single unused sync cord so I can drive one strobe and I have a slave connector so I can drive the other one. At least I'll still be able to take photos while waiting to get things sorted.