All is well apart from when the call to action stack appears, it adds a top offset equivalent to the top menu bar on the page.
To see what I man, go to searchdogssussex.com, look at the top menu bar and wait a couple of seconds. The C2A will appear and when it does, the main body content gets shifted down and I get a white bar that looks the same height as the top bar?
When I look at it on Safari, Top Bar shifts down momentarily as the CTA stack appears but pops back into its correct position a split second later. Then it sits correctly in the page.