Scarlet-chested may not be normal in your area, but has been recorded ca. 100 km. from there, not a very long distance to fly! Having said that, just on colouration, that is a species we can easily exclude. Here's a listing of other species that could occur in your area. Several of these may not be regular, but their distribution comes so close, that they could be expected as occasionals:
Malachite Sunbird*
Scarlet-chested Sunbird*
Amethyst Sunbird
Whitebellied Sunbird
Yellow-bellied Sunbird*
Collared Sunbird*
Marico Sunbird* (don't know why I thought of it this morning! Perhaps it was a little to early
)
Greater Doublecollared Sunbird*
Lesser Double-collared Sunbird*
- the species marked with a * are fairly easy to excluded as the bird on the photo.
So, we are left with two species. The following info is from my own observations (a) and various books (b) I have covering these species (I have excluded various guides only covering these species in other countries, as there often is much geographical variation):
1) "Southern African Birds: A Photographic Guide" by I. Sinclair & I. Davidson
2) "SASOL Birds of Southern Africa" by I. Sinclair, P. Hockey & W. Tarboton.
3) "Collins Illustrated Checklist: Birds of Southern Africa" by B.W. Berlo.
4) "The Birds of Africa" vol. 6 by C. H. Fry, S. Keith & E. K. Urban.
5) "Birds of Africa - A Complete Illustrated Field Guide to the Birds South of the Sahara" by I. Sinlair & P. Ryan.
6) "Sunbirds - A Guide to the Sunbirds, Flowerpeckers, Spiderhunters and Sugarbirds of the World" by R. A. Cheke and C. F. Mann.
7) "Roberts Birds of Southern Africa" by G.L. Maclean (a CD-ROM)
Every single female/juv. Amethyst I have seen had a rather distinct eye-brow. All the above books say that an eye-brow always is present in this species; both in the various female and juv. plumages. No matter how hard I look on the first series of photos, it is close to impossible to see any eye-brow, but it could be due to angle+light... The final photo (has it been worked with photo-shop or similar?) has an eyebrow that fits fairly well, is it the same bird as the one depicted in threads 1 & 2? Throat-patch in Amethyst is very much age-dependent. The sub-species of Amethyst Sunbird in Transvaal (thereby incl. Gauteng) is adjuncta. It is generally somewhat paler than nominate (found in the rest of South Africa). Regarding White-bellied: I already mentioned this species in my first thread on this subject, but female Whitebellied is significantly (not just "slightly") smaller than Amethyst, so normally I would consider a mis-id between these two unlikely - of course this depends somewhat on experiance of the observer. Females of the Whitebellied Sunbird are normally white-bellied (!), but they can be rather variable, with some females showing greyish or (rarely) yellowish bellies. BUT, markings on upper breast always indistinct, rather unlike the individuals on the "un-lightened" photos. Bill also strikes me as somewhat heavy for this species, but In could be wrong. Of course there's the tail (t5 & t6) of the female Whitebellied...
The above is complicated even further by the fact that the adults of Amethyst normally moult somewhere in between february and july; i.e. now! Similarly, most imm's start their moult in april and usually isn't completed until after september. Adults of White-bellied has normally finished their moults by now. Finally, I would like to mention something taken from the very extensive (and recommendable) Roberts: "Always look for association with ad mm [=males]"! If you say "males were in the bush a min before" it reveals little. What is ment by association is, that they are actually seen together...
Whatever the ID of the above, I certainly do envy you having a garden visited by (at least) three species of sunbirds! Certainly makes "my" House Sparrows fade somewhat!
*** The last photo in the previous thread shows an obvious male Whitebellied. Absolutely no doubts there!