Shoulder covering loose(?) Sleeves - t-shirt length, or 3/4.
Summer fabric, (but thick enough for sun protection)
Not highly patterned
Bum covering
NOT shapeless! Must have a waist: tie/ shaped or even elastic 
Smartish. To dress up between gym and shops or smart casual for work.
Up to £30? I would prefer cheaper, then I can multibuy!!!!