Busy - but not a bee

Went on another bee hunt this afternoon as there were some different ones on the comfrey - but then this little one caught my eye on the hybridised cowslips. All three photos feature the same bee fly - the version on the left is just displaying the paler hairs on the underside. The wings were beating very quickly to hold it in position as it gathered nectar - many shots just had them as a blur, despite the camera firing fairly rapidly (natural light, not flash). As this is a composite of 3 cropped areas there's no metadata displayed, but I've put the details in as tags.