Is no news, bad news on the Northern Line?

Some readers will remember that I wrote to the General Manager of the Northern Line about the mooted proposal to permanently split the line between its Bank and Charing Cross branches. Having sent my email on 6 December, I enquired as to a reply on 19 December, and received a note on 22 December saying:

"I am currently investigating the various points you have raised. Unfortunately, this is taking a little longer than I had originally anticipated. As soon as I have all the necessary information I will write to you in detail."

I do not appear to have heard anything since. I appreciate that this is a very busy time for everyone at London Underground because of the severe weather, but I have today emailed again requesting a reply to my email of 6 December. I wonder what I wrote that is taking so long to investigate?