The Date Field Type in Alteryx requires that the format be YYYY-MM-DD. The advantage of this is that you can now do math with the date functions. However, we do also realize that for reporting purposes in the final output of your workflow you may want another date format. This is where the Date/Time tool comes in to play. Many people use this tool to convert their dates from string format (ie. Anything other than YYYY-MM-DD) to the YYYY-MM-DD format. However, a commonly missed function of this tool is that it works the other way as well.
As you can see in this screenshot, you will want to take a Date Field and convert it to a formatted string. In the box below you are declaring what format you want your output to look like (in your case DD/MM/YYYY). The tool outputs a new field called DateTime_Out which will contain your newly formatted string.
This avoids you having to use a Formula tool and breaking apart the date string and pieceing it back together manually.
Hope that helps!