Sunnywa seems to have the most logical explanation regarding why the APP1 approach was used to 200ft then the APBSS route guide towards Blacksod. In summary the crew knew (a) APBSS was probably VFR, (b) the cloudbase was around 300ft hence the need for a 200ft VFR transit, (c) that their SOPs mandated any over sea IMC let down had to be well away from the coast and (d) that as there was no IFR arrival plate this was their only option.
Of the many issues, firstly what SOPs do apply to the ICG SAR for IMC let downs? If there is no IFR arrival plate (which presumably for most of their non airport destinations there isn't), exactly what are the crew permitted to do? Presumably creating their own safe let down procedure is not a permitted option?