My guess would be some sort of wild eggplant, or eggplant hybridized with some wild solanaceae. But just an uneducated guess on my part.
I will be interested to learn what you've got there also when the experts chime in.

I grafted female onto a male carob and it worked perfectly, it is now full of it's first pods. I left one male branch for pollination purposes.

The website is down which described the varieties, and I don't remember the characteristics when he showed them.

Here you go...

http://www.socalplantbreeders.com/#!mango-varieties-currently-avai/comb

Psidium eugeniaefolia maybe

scales also attracted ants climbing up and down the trunk. tanglefoot? other sticky barriers?

The ants are farming and defending the scale. Tanglefoot is the way to go. Just make sure you don't paint it directly on the trunk, I use surveyor's tape, it's cheep and somewhat stretchy.

Doing some (very) quick reading, shouldn't guttation be more water like than sticky and glue like?

I've never seen that happen on it's own, but I have seen exactly that with soft bodied scale. It will drip down from above and land on the top side of leaves.

lotusblos, That is indeed CLM damage.

Yes, definitely candlenut, Aleurites moluccana

BMc what are they grafted on in Australia, do you know?

From the article posted above by ASaffron

Although no formal rootstock trials have been undertaken for finger limes they are most commonly budded onto Citrus trifoliata or Troyer citrange rootstocks. To date no obvious incompatibility on these rootstocks has been reported. C. trifoliata is the preferred rootstock for heavy clay-loam soils or in areas with high or frequent rainfall. Most finger limes grown in coastal areas are budded onto C. trifoliata for protection against Phytophthora root rot. Rootstock choice should always match soil and climatic conditions.