After a brief skype session with Ray. It was discovered that the issue was with the way dmx client side validation was using javascript to submit the form but the submit button was not including the form button in the submit, consequently the insert record behaviour was not triggering.
The solution was simply to add hidden fields with the same name as the submit button. These hidden fields will then trigger the insert behaviours.
<input type="hidden" name="submit_pcd" value="Next">
<input type="submit" role="button" id="submitPcd" name="submit_pcd" class="form-control btn-green" value="Next">
Simple solution for anyone wanting to use Wappler with DW and webassist for web forms.