Hi. My apologies, I am just an interested civilian so I'll be brief.
IAA ICAO charts use a red circle as the symbol for a lighthouse.The "Approach Blacksod South" route guide being used had two of these red circles. One at BLKMO marked 282. One at BLKSD marked 43. According to Irish Lights those heights given are the heights of the lights on the lighthouses in those two locations.
So the map provided seems to provide the information that BLKMO is a lighthouse at 282 feet ASL.
I think it was unfortunate that the hazard warnings were also in red circles, albeit slightly larger, and even more so that BLKMO was #1. That left open the possibility of misinterpretation that it was a starting point, not an indicator to refer to the written text.