I concur that you should be able to remove the partition for access. If your filter is same as mine, 2011 360, it would be too difficult to remove thru an access hole. The filter is designed to be removed and reattached by plastic wrench, which slides over the bottom of housing up to just above middle portion. PS my housing and filter are located at your city water connection, have you checked that location, as my water pump is located behind a partition with 5in cut outs.
Logic will carry you from point A to point B. Imagination will carry you everywhere. "Albert Einstein". 2011 Georgetown 360, Bride of 45yrs, and 2014 Chev Equinox toad, what more could you ask for.