galah681, You can distinguish Weebills and Yellow-rumped Thornbills by their short stubby bill, smaller overall size, pale brow, and the absence of the black cap with white spots. Weebills tend to stick higher up in the caopy while YRThornbills will often feed on the ground and use the lower canopy
I didn't think these birds were as small as weebils and they were doing short cheeping calls as they flew between small eucalypts. They were about 2m above the ground. I thought they were probably immature birds, but there seemed to be some speckles on their crown.