Subfloor / substrate - advice

[Don6600]

Hi after some thoughts on my intended ideas for the following job. Any reccomendations would be welcome.
Looked at a job to tile floor of en suite bathroom. The previous tiles have been lifted and the full bathroom suite removed. Toilet / sink / shower tray. I can see there is weyroc floor overboarded with 12 mm ply. The shower tray sat straight on the weyroc. On testing the floor it appears it is reasonably solid, no great movement.
Ii am unaware of type of ply. I was considering hardibacker board in area for under shower tray. I am building a frame as tray needs raising for drainage. Thinking ditra matting over existing ply. The tray was cut into plasterboard so will attempt to tank round edges of tray as best possible.
Am hoping this would work as think if ply comes up whole subfloor will need replacing. Sorry for long post. I took a couple of pics but don't know how to attach

Cheers Phil

 

[White Room]

Hi and welcome.....What tiles will you be fixing to the floor...

 

[Don6600]

Hi thanks white beam. There a good quality high gloss ceramic. Can't remember size off top of head but reasonably large

 

[White Room]

Is there any chance of ripping up the ply and glue and screw 6mm hardie on the floor.....

 

[Don6600]

Could give that a good go. Just hoping it doesn't destroy weyroc underneath. There is a section of ply hidden under some boxing but I'll just cut that section out.

Would the hardie compensate some minor damage to weyroc surface ?

 

[White Room]

Minor damage as in ????

 

[Don6600]

The surface of the weyroc. I can see its screwed and assume its only bonded with glue I hope.

I'll just crack on with that if ok'd. Should be easier than my idea.

Thanks again