I was an Isted before I married. I think many of the people tracing their Isted/Histed family history have heard the tale that the name originally comes from Scandinavia. Some say Sweden, some say Norway.
From my family research I can see that the name has been spelt many different ways. Only one of my branches has spelt it 'Isted'all of the time- They were the rich & probably well-educated ones. The rest were probably reliantfor spelling on the whoever they dictated the name to.
Bruce Isted from New Zealand has done a lot of work on the Isted family and he has traced it back to around the 15th Century.He has a lot of interesting stuff to say. Try emailing him !
As to your own family, do you come from Croydon ? Perhaps you would like to email me privately with some details of your date of birth/ parents names etc.. maybe you fit in my family tree.