Premium started off as an ADSL Max option, where it costs £4/month (exc. VAT) wholesale and £10/month (inc. VAT) from A&A.
When the network links to BT reached their committed limit and it took time for BT to react, the concept of LNS premium was introduced to give priority to those lines when there wasn't enough bandwidth.
On FTTC the 10mbit/s upload option is £1/month (exc. VAT) from BT [Wholesale]. There are other FTTC options available such as "Elevated Best Effort" too that may or may not be part of A&A premium (from the description it appears that it might be).
These need to be split up into separate pricing options otherwise it's necessary to pay £10/month more just to get 10mbit/s upload when the other features are not required and the actual cost is only 10% of that.