Baby freshwater crocs seem to be a little less skittish than their mum and dad. Usually a mature freshie will take off in a heartbeat when it senses movement.
Just for the record, I'm a complete novice when it comes to photographing wildlife after dark. Learning on the job, so to speak, and excited to be learning. Sometimes a spotlight is enough to get a reasonable exposure, sometimes the flash does too much, other times not enough. Really keen to minimise any disturbance and just enjoy watching these little critters do their thing. These close encounters with native wildlife are a nice reminder that it's not a big empty landscape out there - it's a living breathing ecosystem that is hugely important and deserves to be protected.