Green’s Dictionary of Slang

rob-o-davy n.

[? SE rob + Davy, the Welsh name Dafyyd, anglicized as Taffy]

metheglin or spiced mead.

[UK]J. Taylor ‘Praise of Hemp-Seed’ in Works (1869) III 65: Peter-se-mea, or head-strong Charnico, / Sherry, nor Rob-o-Davy here could flow, / The French frontinixcke, claret, red nor white, / Graves nor high-country, could our hearts delight.