As in the subject line, I can receive and send from home and various friends homes and hotspots but not send from here I can only receive, although I can send if I use a dongle.
pop3, ports 110 & 587
Welcome to the Community @pedward132
Since there's no issue with your Email account as it is working on other connections, then you might need to change the Outgoing mail server on your Mail client if you are going to use the Hospital guest network.
You need to identify the service provider of the Hospital and search for their Outgoing mail server to be used.
However, you need to make sure that you change it back to the original mail server once you've disconnected to the network.