Liam We are pretty sure it was a Peregrine and not a Hobby - size, relative length of tail and wings, and length of tail/wings cf body length. Hobby is Falco longipennis because of length of tail/wings cf. rest of body. Head colour too indicates Peregrine.
Definitely a Hobby. Peregrines have a full black helmet, their breasts are barred rather than streaked (in adults), and they have a much paler belly. As for the darker colour of the bird, that’s probably just because of the light.