I have recently updated to WeatherCat v3.05 and after getting the first rain since the update noticed that the totals were not transmitted to my webpage (Meteotemplate). More strangly, the rain rates were transmitted normally, just not the totals. Everything seemed to be in order with WeatherCat, so it looks like something odd with the Meteotemplate API included with WeatherCat not sending rain total data.
Restarting WeatherCat seems to have resolved the issue as the API started sending the correct information but something anyone running WeatherCat should continue to monitor just in case this issue is not just a 'one-off' situation.