My children we ordered back to Israel under the Hague Convention. Does that mean there is absolutely no hope of them relocating legally to me, their mother, to my 'home country'?

No! Even if the children have been returned to Israel under the Hague Convention, in child abduction proceedings, they have a legal right to file, independently, as separate legal personalities, to relocate overseas, in your custody, and you can also file for their relocation.

The court can grant a relocation order even though there were child abduction proceedings overeas , if it considers that this to be in the children's best interests, after all the evidence in the Israeli relocation proceedings has been heard/considered and the summation stage completed . Clearly, to be successful, you will have to overcome the stigma of the 'abduction' and any court-appointed expert who recommends relocation will have to stand up well to cross examination in court.
Our legal practice has successfully represented mothers in relocation proceedings, after they returned to Israel with minor children, pursuant to Hague Orders.