Christine - Sorry - been away. Also sorry your bowl/vase is nothing like I ever saw at Sowerbys (or Davidsons).
Just to add a little to what I said re sets of vase/frog/plinth etc. People nowadays may imagine such sets to be packed together in pretty (or even plain) cartons. No way. At Sowerbys, at least until 1957, every article (not set) was individually wrapped in colour-coded (i.e. amber, green, white etc) tissue after washing and was warehoused and packed like that. Packing was with straw in large returnable wooden barrels (honestly!) or for small orders in tea chests or if the customer had complained that barrels would not pass through his shop door! Individual parts of "sets" might be anywhere in the container.
Tea chests were non-returnable but barrels were individually marked. On return, waste straw was removed (by our two coopers - maintenance of the barrels) and any glass, usually in the bottom layer, was recorded to await the inevitable complaint of shortages.