Calendar Widget - Title attribute has two zeros

Hi,

I'm looking for some help, I'm using the calendar widget to show booking on a weekly basis using the basic week view. The title attribute uses a booking id which has the data type set to auto number but is converted to a string using the toString function. When the calendar widget is renders on the page I get these two zero's before the actual booking id number like in the image below:

Any idea what is causing them and how I can get rid of them?

Thanks.