We have various insects landing on the Dandelions at the moment. This seems to be a new one for my garden list. I am not exactly sure what kind of ?bee it is, but judging by a thread on the Suffolk Wildlife Facebook group, it seems to be a Nomad bee, perhaps akin to Nomada goodeniana, though I fear the antennae are not sufficiently orange in hue for this particular variety. Those two yellow spots made me stop and take a second look. I shall post the photo on iSpot.
P.S. Thanks to the kind (and knowledgeable) folk on iSpot, it seems this is a Nomada/Nomad bee, possibly a female marshamella.