Very much doubt that anything 'new' is needed.
If you're sure the relevant fuse (#24) is good, then a strip down of the switch (easy), and a bit of contact cleaning inside, will probably sort your problem.
One other possibility is that the wiring leading to the switch has been vandalised by someone purporting to be an ICE or alarm fitter. The less gifted ones often go for the hazard switch, as there's always a permanent live wire available there.
well tbh i did notice a small box above the glovebox whilst changing the obc clock, and when i was putting everything back in thats when it stopped working...