From the BBC Legacies website again (part 3):
"Over time, the oratory became a ruin through continued theft of stones by islanders, and by 1575, it was nothing but a shepherd's shelter.
But the lighthouse tower still remains as testimony to the monk's worthy duties.

"After 300 years of the St Catherine's headland being left without any warning light, Trinity House, the UK's lighthouse authority
(constituted by Royal Charter in 1514), started to erect a new pharos.

"It is only the shell of this that remains close to the Pepper Pot lighthouse. It was never completed.
The present-day lighthouse on the point was commissioned in 1840 and is still operational today."