Is this correct plumbing set up

[BobbyJoe]

Hi everyone,

Is this set up correct:

1. Attic stop valve turns off the cold water to my bathroom (I think it is the rising main in the attic which I and other residents in the building share as we have shared supply to bathrooms and kitchens)
2. Under kitchen sink stop valve turns off cold water in kitchen sink
3. Kitchen wall panel stop valve turns off hot water supply in kitchen and bathroom (including shower)
4. Red gate valve cold water feed in airing cupboard turns off cold water in bathroom as well
5. 12 LPM water pressure in kitchen, 20 LPM on cold water pressure in bath tub, high water pressure on top floor flat
6. Hot and cold water pressure is unbalanced, cold water has much higher pressure than hot water in all faucets
7. Gas combination boiler, one hole lever mixer taps, no dual flow taps fitted in kitchen or bathroom.

I am not sure why I have so many stop valves or if this is the normal as I am sure before I moved into the property there was a hot water cylinder and cold water connection to the water tank but now all faucets are mains water fed. Neighbours are mains fed but have much lower water pressure than my flat and gravity fed electric showers but I have a thermostatic mixer shower .

If you could read the image info, I would like to know would where I should have the double check valves fitted.
Are they fitted after the stop valve or before, does every stop tap need a double check valve fitted so this would be 3 in total (2 in kitchen and one in attic).
Or do I need to have one fitted on each pipe for example, the cold and hot water pipes under the kitchen sink, two each on bathroom basin and two each on the bath tub cold and hot water pipes.

Any information would be very much appreciated thank you.