Dear Ms. Bolshakova,
Kind thanks for your helpful and detailed reply.
In the UK, it does not appear to be possible for an individual to bring a case about this to court directly. Instead, individuals are required to depend on the ICO to do so (as I understand things).
Yesterday, though, I was informed that an Assistant Information Commissioner, who reports directly to the head of the ICO, has taken up my case. I had not expected that: there had been no word from the ICO since mid January. This means that there is a fair chance that matters will now be resolved. For now, then, I would not ask for the Secretariat to do more on this. I will keep you posted on how/if things work out.
With kind wishes,
and thanks again,