Some hopefully useful background for Gibb Sahib, Charley and Lighter.
It seems that this chantey was well-known as a shore song in the late 18th century. I have several versions of a shore song with similar refrains, but unfortunately as yet no tune.

The refrains are
I randy dandy, O
With my rally-pin, gally-pin, dandy, O

It would seem therefore that these are probably the origins of the 'rollocking' and 'galloping' in versions of the chantey, as the shore songs predate chanteying records. Conjecture that Hugill's informants sang 'bollocky' or 'bollocking' may well be true but the originals are much closer to 'rollocking' and 'galloping'.

Rally-pin and gally-pin may well derive from these 2 so we need to check if these actual words existed first.

I have 4 versions of the 'Countryman's Visit to Bartholomew Fair' but the oldest and longest seems to be the one printed by J. Evans and Sons of Long Lane in their songster titled 'Merry Songs' containing 19 songs of which this is number 14. But of equal interest is the song at number 18 in the same songster titled 'New Randy Dandy O' suggesting perhaps that both songs may be based on an earlier one unless number 18 is based on number 14.

Both songs to follow:-