Hi Claire,
I had the same dilema when I was choosing the module units for the level 5 diploma. The rationalisation behind my subject choices represented the areas of the business that I wanted to explore purely on a promotional basis.
i) The Core management unit which is compulsary.
ii) Suply chain management as I felt this would give me a wider scope from a knowledge base over the Transport option (personal opinion).
iii) International business, as this optional unit gives a broader sense of the sector for generalisation and policies.
iv) Sourcing and Procurement, for the understanding of purchasing and how to collate your plannning data for systems implimentation etc.
Think about your career objectives and you won't go far wrong.
Good luck with your choice.
Christian Francis MILT