https://www.minibearings.com.au/
Had 17 mm shims for MED rocker shaft and much more.
Had to go with their local supplier One or two days turnaround time.
Very happy

These guys are also great for shims.
www.precisionshims.com.au.
I asked for a quote on shims lunchtime yeasterday. Got a call within an hour telling me what they had in stock. Have the shims in my hands lunchtime today.
Used them before and they had to make up shims for me because they didn't have stock, took about a week. Prices were very reasonable and no minimum order.