The Party Wall etc Act 1996 came into effect throughout England & Wales on the 1st July 1997 (it replaced Part Vi of the London Building Acts (Amendment) Act 1939 which was only applicable to the Inner London Boroughs).
If you are carrying out work that is notifiable under the Act then it applies to you.
KMASS can review the drawings for a modest fee and advise you whether or not the Act applies.
