Porch, hall and landing lights controlled by two single two way switches. Can I separate the porch light with double switch?

Possibly, it depends on how its been wired as there is more than one way of coneecting this arrangement up. If the porch light is an add on, it maybe just spurred from the hall light and not have a separate switch line at the switch.

if the lights for porch and hall are link together you have to provide separate switch line for the porchand replace 1 gang switch wth 2 gang swith .for more info contact me . emilio

If the switch closest to your porch has the mains feed at it, then the answer is yes. You would identify this by finding out which cable has 240v at it all the time when switched. Then it is just a case of linking the new switch to mains cable and finding out which switch wire goes to your porch light. Best to get a qualified electrician if unsure.

Without seeing the wiring in the switches, my assumption is the cables inside the switch are "switch return" 2 core and earth, and "two way stapper" (3 core and earth) or just the 3 core and earth. This means you can't seperate the light circuits by the switch. This would normally be done by adding a new switch cable and changing the exisiting lighting circuits to change the switching on off of lights independently as you wish. Regards