It took a little digging but I found that the part number for the missing "ring" plate is AUB668.  Our host does not have it listed.  You can buy it from Somerford Mini or Burlen (SU) (both in the U.K.)  I think the screws you need to hold the plate on the pump are AUB660.

Great info. THANK YOU

The barbed elbows the fuel hoses connect to can be turned and pointed different directions.  The ring you are talking about presses down on those barbed elbows to hold them in place.  I would not consider running the pump without that ring in place as the elbows may pop off.

The pump's toggle mechanism (under the plastic/bakelite cover) has to be adjusted correctly for the points to open and close at the correct time.  If the adjustments aren't right the pump will just sit there and not cycle.  If your pump has an intact coil and the points are clean, chances are the toggle mechanism needs to be adjusted.  

I don't remember if the adjustment procedure is listed in the manual but I am pretty confident they are discussed in the SU carb manual.

I recently obtained a '65 Mini that should run but for an AUF 214 fuel pump not working which is in the box of parts. It seems to be brand new. When connected directly to a 12V battery nothing happens. I've cleaned the points. In looking at pictures of this pump online I see what appears to be a black plastic ring connected to the housing (bottom of the attached image). Mine doesn't have that. What is the reason for this thing? Any thoughts would be appreciated. THANK YOU