Can anyone confirm there is no transmission fluid check dipstick, just a plug bolt on the front above the drain bolt with which to check, add?
I am 99% certain that there is no way to check it. It it hasn't been leaking assume the level is correct. Drain and measure what came out. Put back in the exact same amount. I can't tell you where, exactly, but there are instructions out there on the web.
You check by comparing the level to the fill opening. It usually doesn't go away by itself, so the usual reason for checking is refilling after a fluid change.