If you have purchased tickets before your 8 digit Theatre Royal Bath account number is on the left hand edge of your ticket, printed vertically. Your password is your postcode (including the space), and you will be prompted to change this when you first log in. Your 8 digit account number is also printed on any previous online booking confirmation and is the last set of digits of the Reservation Number.
You can however look up your account number using the "Forgotten Your Account No.?" link below.