I have 2 accounts, each entitled to 200GB of BT Cloud storage. But it is impossible to access the storage associated with the 2nd (non primary) account. I queried this in a discussion with support and she said Tier 2 would look at this. They haven't got back to me.
It would be more convenient if the 2 lots of 200GB could be amalgamated into 1 lot of 400GB, but I could live with the 2 separate chunks I am paying for.