Summary.
north aisle generally agreed to be mid 12th century.
south aisle added later - some say 100 years-or so later— possibly on the site of the 2nd oratory although it's not proven.

Ecclesiastical status
When the abbey was built, the chapel became the Grendon chantry and survives as the present church of Dale (C40F, C/WC).

The gallery was for the use of lepers, not mentioned in the Abbey records (FOX).

The church’s status is discussed in C43.
The church was without a proper minister (using the Risley Hall chaplain) until 1702 when "it was united with Stanton" (C43).

Status as ‘peculiar’: vicus Dale, cuius ecclesia parochialis facta est capella antiquorum prioratuum de Depedale, etiam post abolitionem cultus catholici remansit exemptus a iurisdictione episcopali (PREMONS);  
in the jurisdiction of Dale Abbey, Earl Stanhope the lord holding annual court and appointing the minister 1846 (LYSONS records him appointing ministers)
the last earl died 1968;  the line is now extinct
between 1940 and 1950 the church passed to the Commissioners

The church records 1667-1813 are in www.londonfhc.org

The graveyard has the tomb of Ralph Taylor died 1790 aged 84 and his wife Elizabeth 96 (LYSONS).

Source of these last 2 items (?) is an article in photocopy, in folder, source unknown but pp. 114-117.