This grower is sure of this plant identification.
I would spit and divide this plant especially for you, so size is a rough estimate.
Lady's mantle, Alchemilla grandiflora hort.
Alchemilla mollis (Lady's mantle). This is the most widely cultivated species. It is a low-growing, clump-forming perennial with soft grey-green, fan-shaped foliage. Sprays of tiny pale yellow flowers are produced in the summer.
These plants will often self-sow and you should remove the flowers before they set seed, if this becomes a problem.
Border, edging, ground cover, cut flowers and walls. Summer interest.