[Neil]

You had 3 pieces of equipment switched on that probably all pull 10 amps or more. Add to that the other electrical equipment plugged in and you were overloading that 30amp fuse which caused it to get warm. A photo of it would have been a nice reminder to other people to get theres checked out. You probably have a bad connection on that fuse causing the heat if it got that hot. The fuse would usually blow if it was that hot. What was glowing? The middle of the fuse or one of the ends?

I am glad you are going to get it looked at, please do it really soon before you have a fire.