With the EU LBT firmware, the D8 mode is not enabled, and since the EU LBT firmware cant be loaded onto the D4R, you cant bind the two. However all you need to do is load the international firmware onto your Taranis to enable D8 mode. (however please check your local regulations if you are able to use the international firmware in your country).
To do this you just need to change the firmware on the Taranis (on the internal XJT radio module) to international firmware (instead of EU). We have a Frsky module firmware upgrade guide, but instead of selecting to upgrade the firmware to your external module, you select internal module to upgrade the firmware.