An absolutely disgraceful Fob-Off letter, one of the worst I've seen. They send these out as part of their gaming of the system to get people to cough-up, and it works !! about 99% of people just cough-up when they get something like this assuming the councils are telling the truth, Ha Ha !
What you need to do now is wait for the Notice to Owner, and submit the same reps again. However post what you sent here and we'll see if we can strengthen it.