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-MooringsThese 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/