A Running Crab Spider – Philodromus dispar 

One of several species of Philodromus that look similar, but we think is most likely P.dispar.

The image here is of a female on a buttercup flower, but we have we believe seen the male of the species in the garden recently, which is reasonably easy to identify, supporting the view this is dispar.

This is a relatively common species and known to frequent gardens.