In reply to Nikki.

Thanks for the tip Nikki. I have got about 30 websites built with Canvas ( some of them are very old) and have started looking for solutions. Some of them are small 5 page websites and others are a bit more complex. All look very different and have varying amounts of custom css (and shortcodes) to make them unique. The GeneratePress theme looks like the best I have come across for using on some of these websites.

Once I work out some options I am then going to have to work out an approach to let my clients know that I need to update their theme...