With the above, the port is essentially complete. I have pretty much gone for the quickest solutions where possible - there are not perfect but they get us sufficiently going.
Concerning testing, the approach I have taken is even simpler. It may even be worthwhile, exploring an approach where essential config settings come from the nunit config file.
Also, I applied some hacks to the code to get some tests working. Ideally, we would have re-written the whole application to allow for HttpContext wrapping - but that was beyond the scope of the present porting exercise - perhaps we will do this for the next port.
Next steps: Look for a release of the completed port project - coming soon. The details will be posted here.