1 Masterbathroom with long bath (1st floor), and two smaller bathrooms (G and 1st floor).

2 options:
1) Share water heater to 3 bathrooms. Piping would take an additional approximately MYR1.5k.
2) Get a smaller storage heater, and 2 individual instant heater.

The only pro that i can think of for option 1 is that the sink for the two smaller bathrooms would have hot water access as well.

Is there a storage water heater that can be left running without switching it off? There will be only one switch for the water heater and it'll be inconvenient