Try the  A40 to Burford then B4425 TO Bibury ( worth stopping here ) carry on the B4425 to cirencester then the A433 to Tetbury   , mainly  national speed limits between Burford & Tetbury  , great sweeping bends , a few twisties , watch out for hidden dips  no gatso,s between villages or  in  Tetbury , Bibury , none on the through road thru cirencester . Watch out for mobile cameras ( never seen one along here myself )