Rhodohypoxis

I would think early spring while still dormant but might be best to Google it.
As I am sure you know they come from Africa so surprises me a little that it thrive in your open garden.
If you are keen to move it to your trough I would split and only put part in the trough reason it will have colder soil temperature in winter simply because its above ground

Yes I agree with Brian Scottish, your trough maybe a bit too cold for it just move a small partof it.

Thanks both for the advice. I'll leave it where it is then. I was always under the impression that they were hardy enough but the wet is what kills them.

Used to have several clumps have lost them all, they were fine in pots, until we put them in the borders....