Is there a way of bulk deleting events from the SD card, as having to go through each day and selecting & deleting events is very time consuming?
Yes. Go to the settings tab for the base unit. Click on the about device tab, and click on format memory card. This clears the base unit, not your phone. All of my phone data is still intact. I just saved myself over 500 button pushes with about 5 and it took me 3 minutes.