Anyway, the root canal seemed to go ok, the tooth was drilled into, the insides removed and filed down, and pressure put on
from the outside in order to remove the puss from the abscess
via the canal. The hole was then cleaned, filled with medication and sealed temporatrily, and I go back next week to have the permanent fill applied. Once the anaesthetic wore off I was in moderate pain but after about an hour it subsided and the tooth felt fantastic compared to how it had felt.