These descriptions are taken from pages 241 and 243 of Fern Grower’s Manual by Barbara Joe Hoshizaki and Robbin C. Moran
Thes are pictures taken from my Cheilanthes in my garden in Waterlooville
There are both scales and hairs on the rachis so it is Cheilanthes tomentosa
If you are unsure it is almost certainly Cheilanthes tomentosa. I cannot remember seeing C. lanosa in an English garden. Maybe I`ve seen it correctly labelled in nurseries, but that might have been in the US. The most obvious difference is C. tomentosa is pale green, lanosa is a richer green. There are scale/hair differences that can be retrieved from any flora, but not easy to interpret unless with good magnification.
C. tomentosa has a pale brown rachis, lanosa is dark brown.
C. tomentosa is ‘silvery’ particularly in the croziers when unfurling, C. lanosa is green.
C. tomentosa is a neater fern with pinnae closer together and slightly narrower than C. lanosa. In C. lanosa pinnae are clearly deltate, in C. tomentosa not so obviously deltate
Image courtresy of Martin Rickard: