Blender over tripling vertex count on export

I have a fairly optimised character model as an .obj that in Unity is 32055 vertices. If I bring it into Blender and export it without making any mods, and then load it back into unity it is then 114,937 vertices.

This is not an intellectual exercise and I do want to make mods to the model in Blender, but did this test to check if it was the mods I want to do or the use of Blender, causing what is a blocking issue in Unity.

I’ve read around the forums and tried turning modifiers off, but not found anything that makes any difference.

Any suggestions gratefully received.

Thanks in advance.