Ok Jason, I forgot to ask you where exactly to put <?php echo(date("d/m/Y", strtotime($row_recordsetName("dateColumn"))); ?> - instead of dateColumn I use memberDOB.
So I've adjusted the code and replaced the following:
value="<?php echo $row_rsMembers_Update['memberDOB']; ?>"
with
value= "<?php echo(date("d/m/Y", strtotime($row_rsMembers_Update("memberDOB"))); ?>"
But I get syntax errors.
Below is my current code (before adjusting)
<span>
<input id="DOB" name="DOB" type="text" value="<?php echo $row_rsMembers_Update['memberDOB']; ?>" class="formTextfield_Medium" tabindex="6" onblur="hideServerError('DOB_ServerError');"/>
<span class="textfieldInvalidFormatMsg">Invalid format.</span><span class="textfieldRequiredMsg">Please enter or select a date</span> </span> </span>