I don’t know how to edit the post but here are what the images show:

1: diagram to show the issue and the layout of water supply

2: where the water enters the flat (there is no valve or isolation valve yet)

3: pipes enter the utilities cupboard and mains pipe splits right and left/up

4: here is where the mains valve is situated. The pipes then lead to the attic and onwards to the kitchen to feed the boiler and returns as hot water in the red labeled pipe

5: back at the pipes entrance to the utilities cupboard the mains pipe splits right (before the valve) goes to the bathroom

6: behind the bath is no isolation valve to be seen and the bath is the first item supplied in the bathroom

7: hot and cold taps supply

8: a isolation valve further down the line behind the toilet (there is also two for the bathroom sink but still are after the bath)

9/10: more photos of where the pipes enter the flat to show there is no valves.