Passenger Door Light staying on (switch problem)

[The JudGe]

Hi people,

As above the light keeps flashing off & on, especially when I hit some bumps lol. I'm also having the car alarm going off if the door light stays on, so basically I need to replace it.... where would I get a replacement part please, not paying for the earth either.

Any help would be appreciated

Thanks

[The JudGe]

Anyone