Dear Peter
The cuckoo bee foraging on the Oxford ragwort is indeed Nomada goodeniana, a widespread species at this time of year. It is one of the few Nomada which can be reasonably confidently identified from a photograph. From the darkened segments on the antennae, yours was a male. It will also have a characteristic pad of short hairs on the underside of the base of the hind femora, but this will only be visible under a microscope.