Cripes bi-annual - over here (Sydney) it is once per year which fully satisfies RMS and the insurers - who sent you that letter? Realise you get some fierce wind over in the west but so do we over here.

See here past post on pick up post if you want to make one yourself.

www.seabreeze.com.au/forums/Sailing/General/Standup-Moorings

These people could do the inspection work but they might be high end of town..........they should be able to recommend a suitable company for a 24footer.

indianic.com.au/mooring/mooring-installation-services/

I've been using Indianic to inspect my mooring in Freshwater Bay in about 10m of water. It cost me about $400 for the inspection, report and provision of the 3 man dive team. I've been pretty happy with their service.

Interesting that the DOT inspection requirement is only every 2 years. Indianic advise me every 12 months that my inspection is due! I'm not sure if that is them making a bit of extra business for themselves, or if I'm still on their records as needing an annual inspection (when I had a mooring at Nedlands YC they required annual inspections for the non-DOT mooring).

Either way, its a reasonable price to pay for piece of mind.

In answer to your question 2: I have two short bridles with an eye splice in either end. I loop one end around the supplied bridle from the buoy (which is very thick rope and won't fit around my deck gear on my 22ft boat). The other end of these smaller bridles goes around two separate cleats on the foredeck. I keep a good eye out for any chafing on the whole setup, but so far this hasn't been an issue.

DOT usually post out a list of qualified mooring diving services that they will except as contractors.
ring around and find the one that suits you, I found Indianic to be on the more expensive side.

+1 for the standup bouy, so easy!