This grower is fairly sure of this plant identification.
Masterwort, Melancholy gentleman, Greater masterwort
Astrantia major (Masterwort). This perennial has large lobed leaves and they will form a neat clump. The flowers are pink or white and disc-shaped, and they will bloom in the summer.
They will prefer to have soil that does not dry out.
Naturaliser, cutting bed, dried arrangements, borders, under shrubs. Summer interest.