visionx,
Normally they will not except any new information/documentation other than what they have already received along with your HSMP application. If that is the case, then your second review will also not be fruitful.
You havent mentioned how many points your received in your application. If the case workers accept the new details and you are awarded the points for work experience, would that be enough for your approval? I am trying to ascertain weather it is worth your while to have a second review. You mentioned that the contact numbers had changed. What about other channels of contact, like email address and websites? Have they changed too?
You could write a letter to the HSMP team and request a second review. Make sure you have given valid reasons for asking the review and let them know that you have contact details of your old employer. They may or may not accept it.
What do they normally ask to employers? What sort of questions do they ask to verify my reference?
I would imagine, they would like to know if you have worked there in the past and if the positoin you held in the company corresponds to the references you have provided them.