I suspect the subject of the "Oh Aunt" lyrics have cropped up somewhere in these threads. Though an interesting idea about hare-hunting being a folk-metaphor for sex has been offered on another thread, it didn't explain how that linked to the characters in these various versions. I think that "Uncle" is the undecipherable mishearing.
I'm sure it was Emily Slade [as was then]/Jones who said that the (or a) source (for her version) was recorded in Cobham, or Chobham (both close together, in Surrey). He was a strawberry picker. No idea of her source for this info.
But…  that area is near enough, back then, for an East Londoner to have reached it for casual employment in fruit-picking, so I'm guessing the singer was a Cockney(-ish). Charles Dickens indicates the Cockney origins of more than one character (Magwitch, in "Great Expectations", and Sam Weller) by giving them the speech-quirk of substituting a 'v' with a 'w'. To such a speaker, "Oh Aunt" is a rendering of "Ovaunt". Was it Gardiner's (and mates') transliteration of a word they couldn't decipher and the (posited illiterate) singer couldn't explain, into a phrase that at least exists in English, even if it made no sense? "Ovaunt", though, isn't a million miles from "Avant", a French word easily given a new-ish life when pronounced in English;  the more so when given a French pronunciation (a-VORN).
And why would an illiterate Cockney be spouting French? Well he mightn't have known it was French: back in the day, spoken English, even in cities, would have contained all sorts of what would now be called 'dialect' terms. We get huge numbers of hunting terms from the Normans:  hence some of us eat "beef" not "cow", "venison" not "deer", "pork" not "boar", "pheasant" (= French "faisan");  and the fox is known poetically as "Reynard" (the Anglo-Norman huntsman's term for the animal as quarry); why wooded areas set aside for hunting were/still are called Chases (e.g. Cranbourne, Dorset), from "la chasse" (=  the hunt).  Even that archetypally British toff term "Tally-ho!" can't escape its French origins (https://en.wikipedia.org/wiki/Tally-ho#Etymology).
  Thus "Avant", either in the sense of a 'battle-cry' exhortation "Forward!", or as a description "up ahead", is a perfectly feasible option, and likely to still have been in use in some (small-C) conservative fields of activity.
  Among the common folk, whose communities were probably less influenced by change than more progressive, early-adopter strata of society, it's likely that Norman terms were still widely heard in some contexts. One thinks of the truism that the country is slower to change than the city;   huntng is primarly a rural pursuit, and is proud of its tradition (whatever many on these pages may think of it), so I suspect that "Avant" is an ancient throwback that both singer and collector were unaware of.
In that light, I'm sure the "uncle" has been 'parachuted' in, to make sense of the "aunt" reference:  I reckon IT is the spurious one (though I can't make any sense of it).
Tradsinger's gypsy version contains the word (mondegrine IMHO) "airgun" (lyrics are posted on another "Gamekeeper" thread).  I'd be equally suspicious of that anachronism, too.  A quick skim-read does not suggest the hunter has a gun:  isn't that the point of having the dog?