If you want to find the origin of this scheme start here and also here. There are still two sites waiting to get the secure storage, one of which is in my street, but then I have been waiting five years, so a few more months isn't such a big deal.
The proposed charges of £5 to £10 per bike per month do seem a wee bit excessive. The original consultation suggested that they could start at £2 per bike per month which would be more reasonable.
It is interesting to note that the secure storage is designed to take up the space need to park on car, and provides storage for 12 bike. Therefore at £5 per bike per month, the bike parking would yield £720 per annum, compared to £28.50 - £371 for the same space. Also note there is a cost to enforcing car parking rules, it is not straight income.
Once the scheme is fully up and running, maybe there should be another look at the cost of storage for all forms private transport... ;-)