However, what we did see :
Several of these (grey seals):
Absolutely loads of these (common dolphins), playing all round the boat!
Dolphins are really hard to photograph - they are so quick and by the time you press the button, they've gone under again - and the boat moving up and down doesn't help either. The rapid fire mode proved to be the best approach - you do end up with a lot of photos of sea, but also some of dolphins.