I have been struggling with crumpets for a while. I've tried several recipes and always ended up with blind crumpets (no holes).
So I gave up for a while but not liking to be beaten, I decided to have another go. This time I tried Andy's (Ananda) TFL recipe from way back.
To my surprise I had success! Nice tasty crumpets with open holes, crispy exterior and good flavour. One thing that stands out with Andy's recipe is the large amount of yeast used - 6%! But it does seem to work.
Note that this is 6% fresh yeast. I used fresh yeast. If you ever try this recipe and use IDY, multiply the yeast quantity by your favourite factor - I use 0.4X