Yep, i found it....sorry i was only looking at the "EPG Import Configuration" as opposed to the "EPG Settings". I have now configured it to save in my Ext HDD. I will watch it for some days and see how it goes. Meanwhile, see current settings below and let me know if they are ok.If the hdd is initialised you don't need usb.
Go to epgimporter /settings
In there you have the option to save to internal flash or to usb or hdd
I'm out now so can't send any further information