After many days reading up everything I could find online about port forwarding, static ports, stealthy ports online gaming etc. and despite trying everything suggested by the many helpful and informed members of the online community - unfortunately without success. ;( However, picking through the logs in detail finally exposed the culprit: - Aladdin Systems “Internet Cleanup” ver 3. This excellent freeware program although apparently turned off; rather too successfully still continued blocking all the ports! However, now revealed it was a simple matter to dig down a couple of layers within the “Browser Guard” section and with the click of a mouse clear the offending box and completely neutralise the monster which had held me at bay for over a week! Oh what joy! :+ So very simple when you know how!
Thanks to everyone in the various forums for the help and suggestions... I just hope this post may go some way to help some other poor soul grappling with the black art of port forwarding, static IP addresses etc.