This ant looks generally very similar to Dolichoderus doriae but I think it is Dolichoderus scabridus as it doesn't look like it has spines on the shoulders.
Hi SWhishart, I've looked at this again (must have too much time on my hands) and really can't tell if it has spines on the shoulders or not, so have suggested changing the ID just to Dolichoderus sp. Does that sound OK to you?
I've had another look at all the photos, not just the posted ones, and I can't see any spines on the shoulders although there are some lower down on the body (base of the thorax or according to one diagram found by prof google, the ants have propodeal spines) but I'm more than happy with making it a more general ID.