Which Bird?

We are close to the sea at West Runton, near Cromer in Norfolk and the air is full of various bird song and we trace one sound back to this 
little fella' (?) and we thought it was a Skylark . Don't laugh. 

However filled with the joy of a half decent picture when I got home I looked it up in my Hamlyn Book of Birds of Britain ( £1.25.....must get a new one) and couldn't find it!!

So what is it ? Not a Sparrow?? or a .....HELP!

And .....Mrs UE swam in the sea at Overstrand near Chromer and she was the only one in> And I took this picture and she so 'don't you dare put that on Blipfoto. So here it is.