I totally missed the form. Now that I think about it I realize that somehow I mixed it up with the Additional Dependants form that doesn't apply. Anyway they have everything nowAre you sure you did not miss any signatures or information on this form ( you submitted just a few days after invited? You submitted on April there are no reason to ask you update new form? And remember not ONLY imm5406 was updated, if your forms were out of dated, they will ask for imm0008,imm1344,... it looks natural if they remind you must submit the most recent forms