The reason for no tours getting as far as the Holyhead breakwater is simply because it was physically isolated from the national network by quite a distance.
As for getting withered at Skeg, I once caught a lunchtime dmu from Beeston to Skeg on spec, and was delighted to find 2 required 20s at the head of the evening Leicester stock. I went into town for food and drink, and a lie down on the beach in the sun. I made my way back in plenty of time for the 18xx Leicester, and find it in platform with nothing at the head. It turned out that the 47/3 on the Sheffield had failed , so that had already departed 17xx with our 20s. We were then told that Lincoln were arranging replacement power. This arrived well over an hour late, as 2 dud 31s. So I was bowled, and back home mega late. Luckily I had gone to Beeston by car.