Do I need to plaster or render under the bath

[GB2465]

I have pulled out an old bath and am putting in a new one. Having pulled out the old bath I've noticed the rendering and plaster on the walls under the bath is decayed and damaged (see photos) from damp over the years I imagine. Do I need to repair this before putting the new bath in? If so, is it a relatively straightforward job or something more complex? I can paint and decorate including filling, but don't have any experience on bigger jobs like this.

 

[CountryFan]

Personally I wouldn't bother and just fit the bath as long as you can get a fixing. What I would do is treat any mould first.

 

[ree]

OP,
Given the state of the multi layers of plaster - & the tile on tile surround - & the amateur plumbing - & the signs of heavy mould & possibly wet rot - then perhaps its worth thinking about doing a bit more than simply trying to fit a bath?
If you wanted help to do more then come back here but if cost is the issue to doing a bit more then just go ahead & fit the new bath.

 

[GB2465]

Thanks to both of you. I guess I could leave it as it is and carry on or do a whole lot more. I'll probably end up somewhere in the middle ground, eg get the plumbing updated, remove flaky and decaying plaster and paint and treat any mould or rot as you suggest.