Calendar Schedule showing incorrect start time

Hi There

I have set the working hours to 8.30am - 5.30pm and my service (chimney sweeping) is 90 minutes long - customers can choose whether they want 1, 2,3,4,5 or 6 chimneys to be swept.

I have set my time base to 90 and I am using the Time slot calculus method - Minimum time based appointment duration calculus (legacy) so that my customers are not presented with limited time slots to book.

The issue is that I have is that the calendar on my appointment booking page is not showing the correct start time of 8.30am - it is currently showing 8.00am with the first available appointment being 9.30am. I want the first appointment to be 8.30am, second 10am, third 11.30am and so on.

I have my booking calendar on the following page