LG G3 v20u root script and oneclick root failed - other options?

Hi,

I have a shiny new LG G3 and need to start installing/moving apps on the SD card to free up space: I have 2GB left after 6 hours ownership.

It immediately updated to v20u software. I have tried running the one-click-root software and the root script in this forum several times each.

They both say they were succesful but the phone is not rooted, nor SuperSU installed.

Is there an alternative method?

Thanks,

James