A brick-lined baptistery was dug in the middle of the central bay on the ground floor and steps down into it were dug in the north end.  A narrow channel, perhaps used for filling the baptistery, was added on the west side and a channel for drainage dug at the south-western corner.  The surrounding floor would have been of sawn timber.
Before the baptistery was dug, members of the congregation probably used one of the nearby rivers for baptisms.  Perhaps they used the Mill Avon which runs behind the burial ground. 

A separate room was built at the north end of the first floor gallery and fitted with sliding screens which opened towards the centre of the chapel.  This was probably used by pastors when they wanted some privacy or possibly by preachers visiting from other churches as somewhere where they could stay.  Also, when the screens were lowered the capacity of the chapel would be increased.
Raised pews were positioned immediately in front of the screen with the hat pegs above them easily accessible.  

The segmental plaster barrel-vaulted roof dates from the 18^th century and runs the entire length of the building.  Unfortunately, in order to install this new roof the original medieval ties were sawn through, weakening the structure as a whole and causing the distinctive bowing of the roof line.  To hold the building together and stop it slumping into the alleyway, two rectangular twisted wrought iron ties had to be inserted into the roof at wall plate level. 

The first floor galleries on either side of the central hall were improved by adding panelled fronts, which had inclined balustrades which could be used for holding books.  The central balcony which exists today was probably added in the early 19^th century.