Internal stud wall plate damage?

[jen20]

Hi could anyone help please. After removing skirting boards and a cupboard we have come across damage to the internal stud wall plate. It looks like its had water damage for year from where the old shower was on the other side of the wall. Its dry but it has rotten in places. Does it need repairing or replacing?
One builder told me no, but I'd like a second opinion.

There is a crack at the top of the wall above the worst damage, not sure if this is related.
The last photo shows what it looks like where it hasn't been water damaged

Thank you

 

[Wayners]

Where wood meets plaster always cracks because they move differently with heat and cold so not a problem.
Wood that's water damaged in photo isn't doing anything important by looks of it.
Just treat with a clear primer preserver which will stop bugs and protect wood.
Only need to replace or straighten rotting wood if it's doing something like supporting

 

[jen20]

That's brilliant thank you. Really appreciate your response. I have a plasterer coming Thursday and didn't want to cancel them. Thanks again