If I have structs which have inheritance, then can I represent these as idl types without using the ANY object, ie can I have inheritance with idl types?

CORBA does not support inheritence of structs.

However, you can have interface inheritence in IDL such as follows

module jguru{
  interface BaseInterface { };
  interface ExtendedInterface : BaseInterface{ };
};

In the above, the ExtendedInterface extends the BaseInterface using the ":" operator. Just like in Java, you can then use polymorphism to refer to the ExtendedInterface as the type BaseInterface.