It was a boolean cut... but as I didn't then divide the resulting face up I guess it also qualifies as user error ;-)

No, it wasn't due to "user error."

It was due to ... "boolean cut." :)

Boolean operations are teh Evil... They almost always make a hash out of the topology. Generally, boolean operations in most modelers don't care a bit about topology - They'll massacre everything to achieve the operation, which is usually counterproductive. Booleans in certain very nice modeling packages can do a much better job, sometimes requiring a few different fine-tuning operations, but...

By far, if you have a choice, choose to do the shape by hand rather than use a boolean operation to do it. Unless your program can help you retopo the object or has some sort of nifty "smart boolean" (NO SUCH THING! ;) ) you will always get better results forming the object by hand. Always.

Yes, boolean operations seem to be there to be a general helper for the modeler. But, that is wrong...

The Boolean is a lie!

;)

(Note: Achieving the shape you produced can be done other ways than polygon modeling strictly from scratch. For instance, some 3D modelers allow you to import Adobe Illustrator files (.ai) and other vector image formats. These will generally be imported as "line art" types of volumeless models. (2D Lines) From bases such as these, you could do a simple extrusion to achieve the shape derived from a pattern of curves you created in a 2D application. Also, some modelers have internal "line" tools which let you create the very same sort of objects, suitable for the same sort of extrusion operations. Some of them could even be dynamic, allowing you to change the shape of the extrusion on the fly, simply by manipulating the curve it was derived from.)