Its ancient chancel arch and doorway have remarkable carvings with "grotesque, boggle-eyed monsters", rare beakhead figures and chevron ornamentation.

It is now cared for by the Churches Conservation Trust, and English Heritage has listed it at Grade II for its architectural and historical importance.

[7] The doorway[5] and "delightful" chancel arch[8] survive from that era (both have been dated to c. 1140), and the layout and fabric of the church are still largely 12th-century despite subsequent restoration.

[12] Features described in the medieval period but now lost include a Lady chapel – a recess on the outside of the chancel wall may be a remnant of this – a leaded steeple and a porch, of which there are fragmentary remains.

[4] Also in the 18th century, the chancel arch and chancel roof were remodelled (the nave had already acquired a timber king post roof in the medieval era)[4] Many Sussex churches were restored during the Victorian era, sometimes drastically;[14] St Mary Magdalene's Church was reordered in 1867, but the changes were modest.

These are densely and richly carved with a wide range of decorations, including bizarre monsters and unusual beakhead-shaped designs.

[7] The doorway, whose door has decorative strap hinges, has three layers of carvings in its semicircular arch; they are in the form of chevrons, stars and grapes.

[5][24] Inside, the carvings around the chancel arch – dating from about 1140, like the doorway – consist of "an amazing congregation of grotesque monsters",[21] "boggle-eyed ... with beaks, tongues and squid-like tentacles, that frown and glare at visitors below".

[21] Such "beakhead" decoration is a little-understood feature of Late Norman architecture:[9] in churches, it may have been used to capture the congregation's interest or to inspire fear and awe.

[4][5] The chancel has 13th-century lancets, some of which have stained glass by Charles Eamer Kempe[6] (one, of St Richard of Chichester, has been described as "of exceptional quality compared with most windows of this period [late 19th century] in Sussex").

The south aisle, added in the 13th century and unblocked in 1867 during the restoration of that year, has chamfered arches supported on round abaci and octagonal responds.

[4][7][9] An "interesting"[27] plain Jacobean pulpit of the early 17th century, with legs rather than the usual single stem,[4][9][13] may have been made by a local craftsman.