Nil odor? I don’t know if you can find it locally but it’s available online. The product has a weird scent, but it’s definitely preferable to decomposing small mammal.
https://www.amazon.co.uk/Nilodor-Tap-A-Drop-Original/dp/B0002AST9W
As a smoker, get yourself some tap a drop. Put a drop on a cotton ball and toss it in under a seat.