I think Commons is a wholly inappropriate home for theses. The Commons licence allows changes to the material, which at least in scientific subjects could be disastrous, with results and conclusions being fiddled with. When I was at the Royal Society and then Cancer Research UK they were well aware of this risk. In many contentious areas this would be very likely to happen, from a variety of motives.
What is needed is open access. There are various OA thesis banks, like https://oatd.org/ which is the best way of doing it. It is difficult enough usiing their search, with just theses; imagine trying to find something using Commons search.