distinctive white pencil moustache over the beak. Any ideas?

Hello! Yesterday I saw 2 small-ish gorgeous birds whilst walking at Newhailles park near Edinburgh. Very friendly - just sat on fence post about 30cm away. Fawny colour but with distinctive white pencil moustache over the beak. Any ideas? Can't see anything like it in any of my books or online! It was in a meadowed area. Thank you!