Given the use of the term ‘multipurpose frigates’, in this context, I’m inclined to think this news may relate specifically to the pair of ex-Dutch M-frigates rather than the Type 23s.

Their were modified prior to delivery with an enlarged hangar and flightdeck (for Chilean Cougar helicopter rather than Dutch SeaLynx) and Goalkeeper removed (to be replaced in due course by Phalanx). Chile ordered Harpoons for these ships.

Almirante Blanco Encalada
Almirante Riveros