Constitutional Reform and Governance Bill

It is retrospectivity that I wish to ask the Minister a question about. I can see that there should be a strong presumption against it when it means that a new requirement is applied retrospectively to a person who could not or should not have been able to foresee it. In this case, however, are we not talking about solemn undertakings given to a body of Parliament in order for people to take their seat? Should they not have anticipated that, one day, somebody would ask them whether they had complied with the undertakings that they had given?