It's fine you know polarity etc, so would have been best to have posted a pic having got it correct. There will be a few members who look at these posts trying to gain knowledge, I pointed out the errors as they are a benefit to all who view.
However posting the pic of the inaccuracy with the - symbol will show no harm can be done by placing the probes back to front.
Good job though getting it sorted, perseverance wins through again.