Invasive Cooking Smell from Neighbouring Flat

hans

Thanks all for the replies and suggestions. I have been away for a couple of weeks thus the late response.
I get on well with the neighbours and they have been very understanding and helpful. I only asked about legal rights because the neighbours are tenants, the landlord lives in the US and the building management nor the letting agents seem very cooperative.

I will ask about the filter, although it is strange that the smell suddenly appeared out of nowhere. Unless the extractor seriously went wrong, I would think filter problems would be more incremental.
Suzy - the kitchen is at the back of their flat and does not have any windows.