The issue I believe is due to the browser time zone being BST. The browser is returning the UTC datetime for the selected date with 00:00:00 for the time element. this causes it to move back an hour to the previous day.
Is there anyway to specify the time used witout it displaying? for instance if I set the time to 13:00:00 then the correct day would always be returned and all I need to do it normalise(set the start time to 00:00:00 and end time to 23:59;59) my times to use it in a query.
or is there a way to get the date that the user selected regardless of the timezone in use?