I have been several times to Scotland and Iceland and have been privileged to see many Puffins. In Scotland especially at the Shetlands near Sumburgh Head light house in the south.
And at Iceland at the cliffs near Látrabjarg, an excellent puffin spotting spot. The birds there are exceptionally tame given the remote nature of the area and therefore offer great photographing opportunities. Just be careful because the cliffs are very, very steep.