Hi there @HelenR
. According to iPhone, there isn't a way that you can see the specific device that's connected on your Hotspot. But there is a way that you can see, detects, and even block other users that's connected on your Hotspot and decongest your data connection. This app is called Network Analyzer
, and you can download this app on iTunes.
What this app does is that it scans your Hotspot, since you've configured your phone to become a Hotspot and becomes visible to other users trying to search for any available Hotspot. This app also has an option to detects when some users are trying to connect on your device. There's also this network diagnostic tool where you can tweak your settings and even block anyone that's inflitrating your phone and stealing your data.
You can see the app here: Here