Owing to a printing error on an earlier SUK spec list for my new S3 which indicated TSR was part of the L&K spec - and isn't, can it be retro-fitted and if so, how?

SUK say no, and don't want to know - small print re errors etc.

Take a look at the VCDS topic. If you have the camera and navigation unit (amundsen/columbus) then it can be activated.