Oooh, that is a hairy wee thing. I have grown s.veitchii and the similar s.stolonifera and neither are as hairy as that and it is mostly the underside of the foliage as well as the stems). Nor, come to think of it, is saxifrage hirsuta. Try saxifrage x geum which does look a lot more like the s.hirsuta. .

I love these little saxifrages...which always do better for me than any of the mossy or encrusted types (although I do have to be more generous with watering than I would like). Will probably be a bit easier to identify when it flowers in early summer.

SB, I was pretty sure this was identified some time ago as Saxifraga x geum 'Dentata'. It is a naturally occurring hybrid of S. hirsuta and S. umbrosa.

I also picked up some dentata, which @spswash did identify, and as you can see from this photo it's teeth are more pronounced and it is not has hairy as the OP.