No. You must not start building work on your project until your district has granted final consent. If building work is started before the district has approved a project then this could not only lead to wasted time, effort and money but could even result in legal liability against you and the other managing trustees of your church.
It is also important to remember that if you start building work without consent then your project will be ineligible for Connexional grants and the use of any funds held in trust by TMCP.
Although you must wait for district consent before starting building work, there is still plenty of background work which can be done in the meantime, such as fundraising and developing your project ideas with your congregation, circuit, district and Connexional Officers.