Since iOS version 10 Apple no longer supports the 'remember username/password' from within the CNA (captive network assistant) that appears automatically when you connect to a college wireless network
With the recent release of iOS version 11.4 there is a way to store and recall the uswername password you use to login to the colleges wireless network, which involves creating an entry within 'Accounts and Passwords' on your device
Go to settings then 'Accounts and Password'
Then select 'App and Website Passwords' at the top
Then scroll to the bottom and click on 'Add Password' at the bottom
Then enter the details as follows - sustituting the username/password with your own college username/password
The website address is wlan.bruford.ac.uk
Then when you connect to the colleges wireless network click in the username box and then select the 'for this website' username in the grey bar that appears just above the keyboard
This will then auto fill the username/password boxes
You can then login as normal
When you change your college password you will need to go back to the website password entry created above in step 3 and update the saved password with your new one