Mailchimp and date appearance on separate lines

I am using the Mailchimp embedded code on a page for subscribing to my test blog (knack.com.au). It works well BUT I am having a problem with the appearance of a date field. The format should be dd/mm/yyyy on a single line but it appears on the form as
dd/
mm/
yyyy

ie. on separate lines.

Is there a solution to this?

The relevant code I think is the following

<div class="mc-field-group size1of2">
	<label for="mce-BIRTHDAY-month">Birthday </label>
	<div class="datefield">
		<span class="subfield dayfield"><input type="text" pattern="[0-9]*" value="DD" size="2" maxlength="2" name="BIRTHDAY[day]" id="mce-BIRTHDAY-day"></span> /
        <span class="subfield monthfield"><input type="text" pattern="[0-9]*" value="MM" size="2" maxlength="2" name="BIRTHDAY[month]" id="mce-BIRTHDAY-month"></span> /
		<span class="subfield yearfield"><input type="text" pattern="[0-9]*" value="YYYY" size="4" maxlength="4" name="BIRTHDAY[year]" id="mce-BIRTHDAY-year"></span>
        <span class="small-meta nowrap">( dd / mm / yyyy )</span>
		<div class="fake-date"><input type="hidden" class=" date" id="BIRTHDAY-fake-date" value=""></div>