I live in a Lovell-built semi-detached house, which was constructed in
2001.

A few months ago some smokers moved in next door. Since then we've
noticed the smell of smoke in the rooms that adjoin next doors house
(our kitchen, dining room and 3rd bedroom). I'm pretty sure that the
smoke isn't coming in through the windows.

Can anyone suggest where the smoke could be entering our property? In
addition is there any way I can confirm the smell we are experiencing
is indeed smoke?

Cheers