There are lots of things you could try... Going in just before the end of a sleep cycle and popping it back in (learning to go from one cycle to the next without waking)... Helping him to find his hands so he can suck a finger or thumb (gives him independance to resettle)... scattering a dozen dummies all over the bed so it's easier for him to find one again (independance from you again)...

There are lots of stages between full-on CIO and cuddling/feeding to sleep every 40 minutes. Sitting by the bed patting, sitting by the bed not patting, patting the mattress (DS hated/hates being touched if he's falling asleep,) going in and out every few minutes, singing or quiet talking, using white noise as a sleep cue, cuddling him to quiet him before putting him down again... there are probably so many other ideas that others will suggest too.

Is he wrapped? Do you leave his arms out? At this age he probably needs a bit of freedom to move in bed, and so trying having him less wrapped might also help. (This was something we found helped a lot, we were still wrapping him at 5 months, cos he seemed to like it, and to go to sleep more easily to start with. But when we started putting him in the light sleeping bag with his arms out, he started to re-settle himself much better.)

But if you call Ngala (I see your location is WA), they will be able to give you some much better ideas - I have always found them to be excellent, especially for specific sleep issues like this. Just call the helpline and ask to speak with someone for some advice.