Rear wheel has had a few spokes replaced over time but noticed recently some are coming loose, as in the nipple actually unwinding! Just spotted one that had all of one turn left on it!!

uneven tension. who built it?

I think once one or two spokes have gone, if you dont re tension the whole thing properly, others will keep on failing or unwinding.

Either rebuild, or detension/retension the whole wheel again.

Cheers, think that’s probably the issue! There’s been some Idiot trail wreckers out round here lately and I’ve had three spokes snapped due to nicely positioned branches, that combined with my “just stick a new spoke in and tighten it” mentality has probably led to this problem!!