OK, something odd is happening. Yesterday I went to book a car for later this year (October-November), with pick-up in Hobart City and drop-off at the airport HBA. Got a reasonable quote and went to write an email to my travelling companions telling them about it. Maybe 10-15 minutes later, when I went back to the Sixt page and refreshed, I got an error message:

SORRY, WE AREN'T ABLE TO OFFER YOU A VEHICLE AT THIS LOCATION FOR THE DATES AND TIMES YOU HAVE CHOSEN.

Long story short: I have cleared all cookies, tried multiple browsers, etc., etc. but now I keep getting that same error message for all attempts to either collect or return a car at Hobart City; tomorrow, next week, next month or six months from now: makes no difference.

The only two things I can think of are (1) IT glitch -- but I've been trying again today and it's the same story -- or (2) maybe they have closed / are closing the City office? Funny thing is that it remains as an option in 'Find a location', showing both street address and opening hours.

Any insights? Cheers.

It looks like the city location is not taking any reservations for pickup beyond July 13th right now. That could be because they are closing it, or it could just be that they are blocking bookings for whatever reason. It's hard to say for sure.

Note that I am seeing lots of availability around the same period for the same rental with Hertz, Avis, Budget, Dollar, Thrifty, and Enterprise, although you didn't specify your dates, so YMMV. You might want to put in a quote to AutoSlash and see what comes back.