Here's what the Council has confirmed to me:
Free swimming for over 60’s was removed when the leisure centres re-opened on 2nd December 2020. The new concessionary price is £1.55 (standard price £4.55). These changes were unfortunately necessary due to the ongoing financial impact of the pandemic.
Greenwich Leisure Limited (GLL) who operate the council owned leisure facilities under the name Better UK communicated pricing changes to its members in November 2020. However, a majority of over 60 members have opted out of receiving communication. GLL have therefore provided free day passes for any members that didn’t have means of paying for their first visit back to a leisure facility.