They should bear in mind that the time that you take to prepare your ethical review is time well spent.  The more you can think about ethical review at the very start of your project, building in review points as you go through your PhD, the more chance you’ll have something  that will stand up to ethical review and any ethical review in the future.  It will serve to help you manage your research more generally get people confident that you have thought through any ethical issues of your project.