Hi Graham,
SAP standard recommendation on SUSE Linux is to use the SLES Enterprise for SAP and it does not change even if it is a TDI setup of HANA on VM or Hardware platform
This is a tie up between SUSE and SAP to deliver a standard OS for all SAP Applications, SAP does allow any customization necessary for the Customers. It helps them troubleshoot issues better and eventually helps enhance the support in case of any specific issues on the OS
The below articles should help clarify any questions on this topic(if you have not come across them already)
Please check them and let us know if you have any further questions
http://service.sap.com/sap/support/notes/1944799
Hope this helps
Sunil