Thank you for your advice @Greedy Grubby Grabber.
Having worked on a secure Mental Health Unit for some years earlier in my career, I am very familiar with the DSM-5 criteria used to clinically diagnose a narcissist, as well as being equipped with the appropriate tools for interacting with them to ensure they are never in a position to manipulate me - and I can assure you in that respect I am more than okay.
I never intended to actually follow through and reply to Lydia’s tweet as I am fully aware that in her mind I would just be validating her behaviour, and I would never in a million years give her that satisfaction - I believe the universe will deal with her eventually, without requiring any input from me whatsoever.
Also, I’m not sure if you noticed the edit at the end of my post, but I apologised for my lengthy rant and explained that I was so furious with Lydia’s behaviour that I just couldn’t hold it in any longer ... I thought it was obvious that my post, regardless of how it was worded, was simply me venting here on Tattle without having to actively engage with her, or her merry band of sycophants, on any level.