Ceiling rose pendant fixture emits plasticky ozone like smell after 20 mins of use

[Flurofan96]

The pendant light fixture that is one of these basic B22 pendant plastic fixtures - well the one in my bedroom which happens to be the oldest in my parents house, has recently started to emit like a plasticky ozone like smell after 20 mins of use - I noticed it when I used an 10W PL CFL that was using a Mazda adapter that I found at the car boot sale - I thought it was that to blame. So I changed it to a Wickes 24W spiral CFL and still I get that plasticky smell after 20 mins

I have a feeling that due to the age of the pendant ceiling rose fixture, there seems to be some fault that is causing this and anyhow the cable itself is showing its agev

I plan to get it replaced for a 16W 2D bulkhead fixture