I ran this by DH. He said it depends on the hourly rate for labour. Some mechanics charge around $80-90 per hour. Some even as much as $120. He also mentioned that to get to the starter motor in a Delica requires the front seat to be moved and is quite awkward.

DH also mentioned that mechanics are not above charging more for more difficult jobs (or for jobs they don't really want). At least that's the case for his mate anyway.

Once you get the invoice, you'll have a better idea of how many hours it took to perform the job and what they charge per hour.
You may have been able to get a cheaper price if you'd shopped around. But it doesn't seem as though you've been grossly overcharged.

HTH