Bat Goddess and Guest - yours is the version Peter Hall refers to (see my posting above), merely called 'The Diamond' and with a tune slightly different from the Bert Lloyd one. Question is, are the notes in Greig-Duncan correct? Are the Lloyd notes correct? It's certainly no proof that there are more references to the 1930 date as they may simply have copied what others wrote before them ...

Actually, the whaling book I mentioned above seems to be the most independent of the sources I have, and it does not include The Diamond in the boats lost in 1830:

[1993:] There were times when names and places in the songs were changed to suit a different area. One traditional song, Diamond Ship, had a string of alternative versions. The opening stanza of one went:

The Diamond was a ship, brave boys, for Davis Straits was bound
And the quay it was all garnished with pretty girls around
Where Captain Gibbons gave command to cross the mountains high
Where the sun it never sets, brave boys, nor darkness in the sky
Along the quay of Aberdeen the girlies they do stand
With their mantles all around them, the tears running down
Don't weep, my pretty fair maids, tho' you be left behind
For the rose shall grow on Greenland's ice before we change our mind

The song ended by toasting the health of the Hercules, the Jane, the Bon-Accord, and the Diamond, but in another version the ships had become the Eliza Swan, the Battler of Montrose and the Resolution of Peterhead. [...]
Gavin Greig included in his Diamond Ship collection a mysterious verse about a local girl's love for a seaman on the Jane - 'whose name I daurna tell'. (Smith, Whale Hunters 40)

The bad years ran like a scar through the history of whaling. The most disastrous year was 1830, when out of 91 British ships in the Davis Straits 19 were lost and 21 returned clean. Two of Peterhead's 13 ships - the Resolution and the Hope - were wrecked. Dundee lost two ships, the Achilles and the Three Brothers, and the Baffin and Rattler of Leith were wrecked, as was the John of Greenock. Four of Aberdeen's ten ships were also wrecked - the Alexander, Laetitia, Princess of Wales and the Middleton, whose successor, Middleton II, was to meet the same fate a few years later. Nearly every ship was damaged. (Smith, Whale Hunters 52)