Unfortunately we do not have the required DCOM access to the SQL Server mentioned in this MSDN article but we do have full admin rights on the SQL Server instance.
We can therefore successfully deploy a package to the server and run it using the SQL Server agent but I cant work out how to delete a package from the server.
The only thing I can think of would be to delete the row from the dbo.sysdtspackages90 table in the MSDB database but that seems a little extreme (if not highly dangerous!) to me.
The problem lies with our server management being outsourced and we would have to fight pretty hard to get the required access - is it worth a (possibly 1 to 2 month) costly fight or can I get what we need some other way?