A lot of forms now ask if you have ever entered an arrangement or composition with a creditor - this would include a DMP. I'm not sure how the underwriting status compares to a formal insolvency though.
You could have a chat to Ryan, the expert mortgage broker, who may be able to help you decide if that is one of the things making the decision between an iva and DMP difficult.
You need to enter an iva wholeheartedly knowing it is right for you.