Good question! I went on to the University College London website and looked at their doctorate programmes. Here is an extract: "
Ideal candidates will have a Master's degree with Distinction in Anthropology or a relevant discipline from a UK university or an overseas qualification of equivalent standard." (https://www.ucl.ac.uk/prospective-students/graduate/research-degrees/anthropology-mphil-phd)
So it looks like using an apostrophe is the lucky winner!