Santander/Alliance Leicester shares - what's happening?

[crystaltipps]

I have some A&L shares, which I understand were converted to Santander shares a couple of months ago following the take over. In mid-November I got a really strange letter from Santander, which I didn't really understand. Can anyone explain to me what Santander are doing? Are they selling all my shares? I haven't heard anything further since the original letter (which my super tidy husband has helpfully shredded!).
Thanks for any help anyone can give.