I have finally given up on trying to sort this out. Under both Windows Server 2012 and Windows 10 my Pharo image just exits leaving nothing, not even a crash file. Hence, I have fixed my MacBookAir so that it stays alive with the lid down and I am now using that as my Seaside server. It has been up for the last 4 days so it seems that this is a Windows only problem and (hopefully) not my code.
In passing, I am a high-level programmer in Pharo in that I do not use any special calls or processes. Davids Totally `Objects