<p>Martyn, your hawk is a female <strong>Eurasian sparrowhawk</strong> <em>Accipiter nisus</em> in immature plumage (i.e. a bird hatched in 2015). This is not a speculative identification; I am 100% certain of it. This is THE classic avian predator of garden birds up to the size of a woodpigeon in the UK, and they are particularly fond of collared doves. I see them pretty much daily in my garden.<br>
Best wishes, Nigel (UK)</p>