1st is Helophilus sp. The common one is pendulus but yours looks more like trivittatus (brighter yellow on abdomen).2nd is Eristalis pertinax, one of the 'drone flies'.3rd is Sphaerophoria sp - I think these need dissecting to be sure of the species.
Thanks George. I get a few hover-flies in the garden, if I get a few more photos, I'll post them. Dave: can you imput onto MM please as I don't have this Taxa on my database.