I have found 4 baptism entries of a Mary Hayward, one of which might relate to our Mary Hayward.

These are

• 1735 & 1737 at Littlehampton
• 1737 at Etchingham   and
• 1740 at Ditchling

Ditchling is only a mile away from Keymer, where Mary married John Norman in 1769, whereas Littlehampton is 24 miles away and Etchingham is 30 miles away. Although Ditchling is by far the nearest the date is the least consistent with being 61 at the time of her death in 1796. Consequently I have felt it prudent to leave the matter open until such time as any further evidence comes to light.