Today was spent soldering the Pi Shim and finding out exactly how bad my soldering skills were. Overall though not too bad and once completed it was time to mount the GPS on the microstack and the subassembly onto the Pi.
Once powered up I followed Charles Mao's second Geocaching blog post (link) and updated the O/S, PI firmware and installed app software. Unfortunately I missed a step which was to cause some pain later...
After configuring the GPS Daemon and rebooting the system I looked at the port the GPS was supposed to be outputing text on (/dev/ttyAMA0) and found nothing. Not to be deterred I powered down, removed the shim and tried again... nothing. Powered down again, looked carefully at the config, ensured the microstack was located correctly and the GPS daughter board mounted correctly and tried again... nothing.
Hmmmm. At this point I remembered reading the MicroStack documentation about the GPS Board. I went back and followed their instructions to see if there was anything there that might shed light on the problem. Their instructions included using the config utility to turn off serial port access to the Pi ( the step I had missed earlier). I did that and rebooted the Pi and ... voila... NMEA strings pouring out of the serial port...
So the moral of this story is (1) follow the posts of others more carefully and (2) sometimes looking at other documentation can give you a lead on what you might have missed.
Anyhow the GPS hardware is now up and running (with the patch antenna) and the software loaded for a Python dev environment, next step (for me as a non-Python person) is to run through the dev process with some simple apps to read the GPS data.