If you know Holy Trinity well you'll be familiar with the single storey extension on the south side of the church.  Although it functions as a single space the half at the front of the church was added first in the 1930s and is the Choir Vestry (where the choir robe before a service).  The other half of the room was added in the 1980s and is called the Mountbatten Room (more on that another time).

The present Choir Vestry replaced the original Choir Vestry which is a small, almost subterranean, room under the altar area of the church with narrow stone steps leading down in to it (now known as the Crypt).  The choir at the time must have been delighted with the new vestry which is a huge improvement on, and great contrast to, its predecessor.  A plaque inside reads:

To the glory of God and to commemorate their long connection with Holy Trinity Church this choir vestry was most generously given by Sir William & Lady Carter and dedicated by the Right Reverend the Bishop of Buckingham on Sunday Feb 7th 1932

A plaque underneath that reads

Sir William Carter died on 14th Oct 1932 and Lady Carter on 1st March 1935 their unselfish work for this church held in affectionate remembrance

Sir William Carter was for many years a Church Warden of Holy Trinity and was Mayor of Windsor thirteen times - serving throughout the First World War.  He was knighted for his many years of public service in 1920.

The Choir Vestry has four features that you may not have noticed on the outside of the window facing the college car park (and rather unfortunately overlooking the bin store!).  The corbels are of an angel (representing Saint Matthew), a lion (representing Saint Mark), an ox (representing Saint Luke) and an eagle (representing Saint John).  The four evangelists (gospel writers) are also depicted in the four windows of the Household Division Chapel.