Bathroom tiling help.

I have found everyones advice on this website very helpful and i really appreciate if your taking the time to read/comment

My inv property i have owned for about 5 years now, the older owner did some weird stuff... As per the attached photo (still working on the photo, having some trouble uploading sorry..) you can see there was 2 x layer of tiles in the bathtub/shower combo. Top layer was put on with silicone and grew mold etc so i have (almost) removed. The bottom layer looks to be in good condition and with my limited time i want to get this job done sooner rather than later.
Following the wall down (yes it needs to be cleaned.) but at the bottom you can see there was only one layer of tiles completed and once i have peeled them off its just empty wall with random bits of wood nailed in here and there.

I've had a few tilers come through whom have all rolled their eyes and said unless your retiling the entire bathroom/toilet they arent interested. (One guy offered $500 to clean the silicone with a toothbrush lol..)

My train of thought is to add a layer of tiles to the bottom and use the existing tiles already in place? But im really a novice at this, i recently painted the house, stained the floors and hung some painting/mirrors - this is the extent of my diy ability's... A few friends have tiled previously and are happy to give me some instruction. But. How hard is it? And if it was your place would you lose the tiles in place and start over? Even replace the bathtub as well? what are your thoughts?

As mentioned before i really appreciate your help

 

Photo is attached to this reply

 

Having only that limited photo to go on, I would remove all the tile and backer (if any) reframe where necessary, install a single handle control valve with integrated diverter, install insulation and a vapor barrier, concrete backer underlayment (1/2") and retile the area.

Again, based on the picture, there isn't much to salvage.

 

I'm with Larry on this, start with a clean slate. I assume that the existing tile is just on wall board which is why there is a lot missing along the bottom as it probably deteriorated. They probably installed it with mastic (not silicone) which is not rated for a wet location.

 

Thanks for the reply guys. I only have a few hours a week to work on this but i have remove the tiles. I have a few more photos, the next stage is to remove the backing. Any advice?
Still fighting with uploading images. They will be in the next reply

 

Photos should be on this reply

Any advice or links on how to remove the concrete backer and then the next steps would be greatly appreciated