Hi Frederick, Pothi,
Thanks for your support. I acitvated db and object cache. This doesn't seem to improve the loading times. I contected my hosting provider as I can only use 'disk' as caching option and I'm convinced this is as slow as not caching. I will let you know once I got more info from them (they are also looking into the possibilities of Redis). I also use the CDN functionality.
I also tested (and don't know if I can mention this here) WP Super cache. This pluggin actually improved the TTFB. As this pluggin has some issues with the dynamic parts of the pages this isn't option for at this moment. W3C offers much more options to customize the caching.
As you mentioned Cloudflare will not address this issue alone. I also don't know what the effect will be on dynamic elements. Perhaps it has to do with the Woocommerce plugin.
Thanks again for you time.
Regards,
Jeroen