Which species?

I'm getting a bit distraught trying to decide what bird this is.  Before I went on holiday,  there were lots of brown birds coming to the feeders, but some looked different from the others and I thought it was just young birds and older ones of the same species and thought they were all female Chaffinch.  
Now I'm not sure.  This bird is quite dark and might be a female Tree House Sparrow - or not.  I have posted extras of birds seen before I went on holiday and others taken today.  The first extra I think is a female Chaffinch or perhaps these are all Chaffinches. 

And just to confuse me further, when I went back to look at the bird feeders, there were three Dunnocks in the garden. 

Ater checking on the internet I've decided that the darker birds are House Sparrows.