Quick query re: unlimited package

Evening all,
I am currently on Extra (12 month contract 60GB/month for £11.50/ month) connecting at 17.5 Mb/s. I wish to go unlimited as I regularly hit the 60GB limit, and the extra £1 per month is fine for me (I will move house fairly soon so don't wish to take another 12 months contract out). My issue is on the "change my package page" it estimates my line speed with unlimited as 7.5 Mb/s despite the "current product" part showing 17.5 Mb/s. Is this a "typo" or is the trade of for unlimited downloads a huge reduction in speed.
Many thanks for your help

It's the way the estimating system works and its source which is BT Wholesale. You speed on Unlimited would be the same as on Extra.

BUT!!!!!

I believe the upgrade would restart your full 12 months anyway. It does on the 18-month FTTC Extra >> Unlimited. You may wish to reconsider. Wouldn't you do a House Move anyway, or don't they do those any more?

Thanks for the reply, and it's great to hear that the speed would be the same (as it's currently spot on). i'm hoping that by paying the £12.50 per month rather than £10 per month unlimited package it won't restart the 12 month contract!
Thanks