We have had a page which until recently was ranked first or second by Google UK and also worldwide for the term "Snowbee".  It is now no longer in the top 50. I ran a page optimization report on the url and had a very good score.  The only criticism was that I had used an atypical character in the url.  The only unusual character was an underscore "_"    We use the underscore in most file names without apparent problems with search engines. In fact they are automatically created in html files by our ecommerce software, and other pages do not seem to have been so adversely affected. Should we discontinue this practice?  It will be difficult but I'm sure we can overcome this if this is the reason why Google has marked us down. I attach images of the SEO Report pages 8fDPi.jpg AdLIn.jpg