Thanks for the comments guys.
Some info.
1st shot 1.6sec @f8
2nd shot 1.3sec @f4
3rd shot 1.3sec @f4
Both the last two shots were in Aperture priority
mode with the camera set at -1.0ev to darken the background and the flash at + 3.0 ev. Metering was centre weighted, flash was rear curtain sync for all shots. The first shot was in manual
mode as once it was dark there is no need for exposure compensation and the flash was not having an impact on the shots.
The remote flash (sb800) was triggered using an on camera sb800 as the commander/master, my intention was for the on camera to trigger the remote and not flash the scene. I am not sure I had the setting correct for the camera mounted flash as it seemed to be lighing the foreground in some of the later shots on the night so I dialled it back to -3.0.
I was using the D300 with Nikkor 105vr mounted on a tripod, I was using the longer lens to allow me to shoot from over the water. This is the second time I have tried this type of shoot and there were a couple of problems. I wanted the twighlight effect immediately after sunset but the twirlers turned up late. Apparently "We will be there at sunset" means 20 mins after sunset.
I know to specify a time next attempt. The distance I was from the remote flash caused some problems with the unit being able to fire, although I could increase my distance as the ambient light faded. The light fades very quickly and being able to change the remote flash ev settings from the camera is a tremedous advantage. I needed to use a tripod as my old hands cannot seem to stay still, but being able to move and change compositions was very limited. I framed very loose to allow for the twirlers movement and they were not keen on getting to close to the flash incase they set it on fire.
The only other problem was whan a very small gust of wind blew the light stand over. The imact on the sand stuffed the brolly but the flash was ok, it landed about half a metre from the water, damn, the insurance may have replaced it with an sb900.
Thoughts for next time; Use two remote flashes, arrange the shoot for earlier before sunset and shoot in shade with lots of minus ev on the camera and an nd filter to slow the shutter speed and simulate a darker than actual environment.
Use a monopod.
Shooting the firetwirling was inspired by daughter who twirls, but I am trying to achive the standard as seen in the Hot Shoe Diaries.
Here is one with the lens stopped down to f18 with a 3sec exposure but the flash did not fire. With enough flash and stopped down lens it may prevent the fire contaminating the scene. Will have to try next time.