Although I have resolved this I thought I'd mention it here - it was quite irritating while it lasted...
I've been using PyCharm on Xubuntu (14.04LTS) for a while and decided to have a look at Pyramid about a week ago; I created a new Pyramid project and PyCharm duly did all the installations and it almost worked first time but I had to run a slightly different version of the commands in the README.TXT manually.
But that was minor...after playing for a bit I closed it down and thought no more about it. However I did notice over the next few days a number of Ubuntu crashes - to do with ubuntu-sso-login, which at that time meant nothing to me, and initially I ignored them. However at the end of the week I wanted to run the Ubuntu Software Center/Centre but it wouldn't load at all. And so I did a bit of web searching, and it was all to do with the ubuntu-sso-login which was all to do with "no module named zope.interface". It was a bit baffling but I had read that Pyramid uses/is based on bits of zope and so a few further searches and I found the suggestion to just reinstall zope.interface using:
sudo pip install –upgrade zope.interface
which although it had a compilation error in an 'optional' component did appear to fix the problem - I have had no Ubuntu crashes in the five or six days since and Ubuntu Software Center/Centre runs happily.
I mention this because of the oddity of the symptoms and the fact that my searches did not in fact show any correlation with an installation of Pyramid but perhaps I was just lucky, or unlucky ...