Could this be a Merlin Falcon in North London?

Late this afternoon I looked in our garden and saw a wood pigeon sized bird sitting on the fence eating a bird - then on the grass was all the evidence, it was eating our resident collared dove which used to live in a nest in our old apple tree..

Got out the binoculars, and bird book - the closest we could identify in the book is a Merlin Falcon, however the bird had dark yellow / orange eyes, and Merlins seem to have black eyes. I've attached the best pictures I could take through the conservatory window.

I thought it could be a sparrowhawk, however it was definitely rusty coloured on the chest and lower face...  Can anyone say for sure what it is?

Location WD6 4QB Date: 24/04/12 18:30