Not been there for couple of years, but at South Stack: - view from RSPB tower looking down to grassy patches on cliff face - climb 2/3 down towards lighthouse then look left to grassy patches; have seen Common Lizard down there too
I have had a handful from Penmon Point scoping over to Puffin Island in the last couple of years. You'll need a powerful scope so views are never great. Also good chance of Black Guillemot from here as well, plus Penmon Point is a lovely place if you haven't visited before.