Something a little bit like a nuthatch

Observation - Something a little bit like a nuthatch. Description: A very distinctive little bird - the size of a warbler but more like a more delicately built nuthatch in shape. The most distinctive feature was a black stripe through the eye from the beak. The colour was very distinct but there is a problem with my memo

A very distinctive little bird - the size of a warbler but more like a more delicately built nuthatch in shape. The most distinctive feature was a black stripe through the eye from the beak. The colour was very distinct but there is a problem with my memory here. The back was definitely in two colours - part soft pale grey, part pale creamy beige, changing at the shoulders. The trouble is I can't remember which way round it was. I suspect the head and shoulders were the beige part but i honestly can't be sure. Anyway, I know of nothing like it. The flight feathers and tail were i think darker grey. It was hopping about in a sloe tree making a rhythmic chp...chp...chp. There might have been two of them.