Replaced the MWF manifold (the piece the water filter connects to). Turns out my manifold had a broken valve which not only reduced the water pressure, but didn't prevent the water from flowing to the filter even if the filter wasn't there.
Using the Appliance Parts Pro site - ordered the part and then watched the video on how to replace it - it was a very good video and outlined all the things you would need and went thru the task simply and effectively - which made the replacement process go very smoothly.
Price of the part was also very similar to other places online.