thanks for your posting the reply. I managed to access my old work after all. The funny thing was to do it I saved the Logic 7.1 song files as Logic Platiinum V6.6. Once in this format Logic 8 seemed happy to read the files. Not sure why this is but will try with some other older stuff I have and see if this is indeed the case.
Having opened the song, I found that the channel presets related to the previous soundcard (EMI 2/6 run off easi driver) so I needed to create new audio tracks using my current audio interface (motu 2408 mk3) and then drag the audio onto the new track. Am in the process of doing this but it seems to be working fine.
It's really great to discover the LUG after many solitary hours trying to figure out all this stuff!