iPad and wifi-related question

Jan relies on talking books. She has her iPad with her in hospital, which has the Audible app installed, and the hospital theoretically provides wifi, but after the first day we've been unable to download any books on to the iPad. (It's an iPad 2, still running iOS 6 because the new look that came in with 7 shows Apple's usual indifference to the needs of the partially sighted. I know iOS 8 is better and easier and whizzier and all that, but Jan can't use it so that's that.) I used up her free entitlement to the hospital's wifi trying, and when I tried to buy her some extra time I found the payment form did not include one of its required fields, which made it basically stupidly impossible. But that's another problem, and if I ever find out who's responsible...well. Anyway.

So I dug out my portable hotspot, charged it up, put fresh credit on it, and lugged it in today, and the thing still won't download. Or access the internet at all.

The wifi works, the iPad knows the password and connects perfectly well, and in the past has worked fine with it. It has plenty of free space. I've looked at the settings. I've done everything I know how to do except perform a full factory reset. I've switched it off and then on again.

The only thing I can see that looks as if it might have something to do with it, mainly because I don't know what it means, is an odd little icon up in the top right hand corner of the screen, of a lock with a clockwise arrow going round it. I haven't been able to identify this or get rid of it.

I am helpless, frustrated and close to tears of rage over this. Jan is being very nice about it ("It's just life," she says) but I need to find a solution.

Can anyone help?