Randomisation All participants will be required to undertake a mixed meal test with/without the standard DPPIV inhibitor. The order of the mixed meal tests at visits 2 and 3 will be decided using a randomisation table (StatsDirect), overseen by the CRF statistician. The randomisation is included in order to minimize any theoretical order bias effects (e.g. glucose levels improving through the study, or participant drop-out affecting the third visit more).