Sam,
At Wouter's behest, I contacted AHPC about your charges, and Greg Goodall replied to me as follows:

Quote
I can confirm that Wouter did buy the plans #243 for a Taipan 4.9 catamaran. Wouter’s statement regarding this is 100% accurate.

The boat that Wouter built was a variation of the Taipan 4.9 and when completed it did not fit within the Taipan 4.9 class rules. It was never intended to be a class legal Taipan 4.9 as the intention was to be a F16 catamaran. For this reason the boat was called a Typhoon.

I hope this sets the record straight.