It was not a Survivor....and was a planned destination for refueling.
One that was used by a an earlier flight that same evening.
The Operator had every opportunity to create a known safe IMC procedure for use by Crews....even those un-familar with the site. The Route Guide failed to rise to the level needed to accomplish that.
If it were a Survivor and thus could be anywhere within the Area of Operations then your comment would be valid.....but it was not.
Shortly after the crash, I went to Google Earth and took a gander at the area around Blackrock and Blacksod and noticed two bits of Rock near Blackrock and the thought that went through my mind was that it would be possible for a crew to perhaps over look them or confuse them with Blackrock somehow if the weather precluded visual contact with the Lighthouse illumination.
I do not believe this is the time or place to see a RAF SAR vs Civvie SAR argument be renewed. Pointing out the differences in equipment and procedures is fine....but what is being discussed is how an experienced Crew in a well equipped aircraft came into contact with terrain.