lighting not working - whose responsibility?

We are the tenants. The overhead lighting in the kitchen is one of those horrible fluorescent strips. Since not long after we moved in we have been aware that the wall switch is a bit 'wonky', ie you often have to jiggle the switch about to make the light come on. This didn't bother us, so we said nothing.

Then 2 days ago the light stopped working altogether. Jiggled the switch and nothing happens. Jiggled it again a bit more and light came on for a second but now the switch is unresponsive. Seems like its the switch thats not working.

Told the LA, thinking they would send someone round, but they want us to change the fluorescent tube first, to see if its that. If that doesn't work, they will send an electrician. It says in our terms and condition tenanats are responsible for replacing these tubes, as well as light bulbs (fair enough re lightbulbs).

But the thing is, we are pretty sure its the switch that's faulty, not the tube, and as they are not cheap and involved a trip to B&Q etc, we are not happy. Would we be able to return it if not needed, I wonder?

So my husband is thinking of getting a new lightswitch and trying to fit it himself. Is this a good idea or what would you advise?