I said I was researching, well this is the latest information that I have found. The owners, Stour Side Investments/Stour Side Developments went into administration during July 2017. As of 2021 the administrators, Duff & Phelps, are considering a sale of the whole site. The administration will come to an end on 11 July 2023 and it appears that a company has paid a £25,000 deposit for a fixed price option.
There is a voluntary organisation, "Save the Lido" who have been clearing rubbish from the site (by the ton) and have organised laser mapping of the whole complex, including the underground sections which was completed by Thanet Council. This was during 2020, apparently they were unable to access the site during 2021. Their work was funded by a £44,000 from the Coastal Revival Fund.
Also in October 2021 a large hole in the carpark adjacent to the sea wall has appeared.
In summary, some people are trying to preserve the site, some people are hoping to develop it, the council is interested, BUT it's all tied up in administration.