No, 50meg will be a new tier and new pricing circa £50/month. There's a massive thread on here covering everything you ever wanted to know about 50meg and more besides.
http://www.cableforum.co.uk/board/12...s-started.html
Wow. I can't believe I answered that without even a hint of sarcasm.
p.s. the modem looks very nice indeed. Pity I can't justify upgrading to 50meg.