Starter contains the bromide and iodide missing from replenisher (but present in non-replenishing kits like Tetenal).

I mixed up my own starter when I didn't have any, from a little of the alkali bottle (part A) in my kit, and some potassium bromide and potassium iodide. It worked very well, I don't know how close my mix was, but replenishing over time pushes it back to normal.

You could process a test few rolls through it until they appear normal density you're used to, use that as your working solution. Then replenish from there.

If you're in Melbourne (doubtful) I've got some starter here.