"The AW109SP is designed to be flown by a single pilot and the checks are generally performed from memory without reference to a written checklist."
I think this phrase is an unhelpful generalisation. The checks are clearly listed in the RFM. When conducting training on the factory course, every student will use a checklist. If an operator chooses to dispense with checklists, then it is their own lookout, as it opens them up to exactly this sort of error. I would like to know on what evidence the AAIB has decided this is the norm?