It's great that you shared this information about the compatibility issue with the Compro E700 PCIE DVB-T tuner on Windows 7. If the tuner software is not working properly even after installing the drivers using the Vista x64 drivers, it can indeed be frustrating. It's good that you've informed Compro about this issue, and their acknowledgment means they might be working on a solution.
In the meantime, as you mentioned, one workaround could be multi-booting into another operating system to use the tuner for Freeview. If you encounter any updates or solutions from Compro or find a workaround that works well, feel free to share it here for others who might be facing a similar issue.