I had to check.

It appeared to me that Grace always used the right hand well to add washing powder but to me it just didn't seem right, so I went to the effort of checking the manual, which in this day and age is usually far easier to just find on-line. Usually but LG are a bit naughty by insisting I use IE despite me having software to decode the odd djvu file format they use.
Anyway as I suspected the left hand well is the correct one for my use, so I dabbed a bit of blue on it to remember in future.