My issue has been solved. After installing 3 versions of wordpress and still having the same problem contacted the host. Turned out to be a mod_security restriction set by the hosting company. They removed the restriction and all is grand.
The rule that caused the problem was:
The rule “!(^$|^application/x-www-form-urlencoded$|^multipart/form-data)” is added under mod_security to prevent server from web attacks such as iframe injection or XSS attack(HTML/Javascript injection)