upgraded canvas theme problem with menu/navigation

Hi Jamie

I have just upgraded the Canvas theme on my website http://www.theholidaybuddy.co.uk, in order that I could add a Woo Commerce shop. I followed your directions to do this – ie creating an “old_canvas” file. On my computer the website now looks odd. The menu has disappeared and there is a small black box for navigation which does not do anything when clicked on. The left hand of the screen has lost the background I had and is now grey with a link to only one of my pages (Contact Us) appearing. WHen viewed on my mobile it looks different again but when I choose “view as desktop” on my mobile it looks as I have described above but the navigation bit works (this in fact looks much better than the mobile version). Sorry this all sounds confusing but it seems as if the mobile and desktop versions are confused.
When viewed on two other laptops it all looks fine – the menu is there and the strange grey area and “navigation” button is not. I suspect I am missing something very obvious but have trawled through the forums and all my settings in the Canvas theme and can not find what it is.