tvmo wrote:
Thanks for all the sensible replies. I can't blame the neighbours they
are really nice people and are entitled to smoke in their own home if
they wish.

The break in the partition wall, perhaps by gaps either side of the
joists is the probable answer - excellent suggestion. The smoke smell
is mainly coming from under the skirting on the adjoining wall with
the neighbours.

I've got someone from Lovell coming around this week to have a look so
I've got to get my neighbours to smoke like hell that day.

Thanks again.

Oh..just go round the skirting with some decorators caulk.