I eventually re-compiled all the backports_dvb *.ko files with ref to This post changing it for the upto date sources, and inserted them into backports_dvb folder replacing existing files.
I left my previously compiled firewire modules and firedtv modules as they were.
And it now works. I'm guessing that the dvb-core.ko file had been modified in some way on the last update.
Thank you for the advice. It's a large learning curve for me, as I've never delved into linux based os before.
