The salt cellar is missing the glass liner, so probably just melt value. The muffineer is a pretty piece so maybe a small premium over melt. Does your mustard pot in your previous post have it’s glass liner?
The salt cellar has the Blue glass liners and is 1 of 2 pieces and has 2 original silver spoons and the mustard pot also has it’s blue glass liner and spoon. The Muffineer, are you refering to the sugar caster?
George Nathan & Ridley Hayes.
https://www.silvermakersmarks.co.uk/Makers/Chester-G.html#GN
https://www.silvermakersmarks.co.uk/Makers/Birmingham-GI-GR.html#GN
https://www.silvermakersmarks.co.uk/Makers/London-SD-SI.html#SD
Samuel & Edward Davenport ?
Yes, the muffineer is the sugar caster. As far as I know the terms are synonymous. Great that you have the liners and the original spoons. Do the hallmarks match up? You would probably get a decent premium over melt value for a nice set like that.