I decided to replace the complete shower head and value.
First I would highly recommend getting the Oxygenics shower head. Amazing difference
Secondly for the shower valve i used the Moen
The big keys to the valve is fitting in the small space and the temp control.
No more scalding showers or frozen showers nice balance same temp whilst Amy goes about her business.
I highly recommend these 2 changes and will post some more pictures later.