Very easily doable.

You walk off the VCE flight into the departures area of T4 main so just follow the signs to S gates and it will take you to the train platform to get to T4S.

Once there just go through passport control, up the lift or escalators and the lounge is in the back of the duty free store.

There's no extra security to clear and I'd say depending on the line at passport control the whole thing should take 25 minutes or so at a regular pace.