On a list of the 18 supposedly approved sites for enhancing coverage on DS, Hastings is on the list for the improvement, yet the a516 article mentions Eastbourne instead.
"There will also be a smaller coverage boost for the multiplex along the south coast around Eastbourne" isn't meant to imply there's a transmitter actually in Eastbourne, just that a new transmitter will improve coverage along the south coast in that area, based on the coverage map.
The ITU list of approved sites appears to only list 17 of the 19 new transmitters; the coverage map shown at the Radio Festival appears to indicate Huntshaw Cross isn't one of them. It may be useful to compare with the original list of approved sites - many of which were not used https://www.a516digital.com/2014/07/10-things-to-know-about-digital-2-dab.html
(scroll down) - and wait until the finalised details are made official.