Does anyone know what the strange looking star shaped aerial thing is at the top of this old mast, pictured from back in 1964?

http://tx.mb21.co.uk/gallery/eastbourne-vhf.php

It could be for receiving radio telephones, often in repeater installations the receive antenna will be at the top and the transmit dipoles below. I’m sure someone else will be along soon to confirm what this is - Albert probably knows.

I’m thinking the angle of the photo may be deceptive. Looks like they may be horizontal; perhaps radials (some sort of ground plane), for the antenna above ?

I think you're right.