Approval Workflow.

Hi Guys, I am trying to create an approval notification but having some issues. 

Background. 

I have a VA and lets say its a Boolean called TestVA

I have a dynamic security group called TestGroup. 

If the TestVA = True then you are added to said security group. This part works fine. 

What I am trying to do is if someone sets the value of TestVA to TRUE then I was an approval workflow to kick off to approve the change. I have created a simple workflow. 

Operation: Modify properties of User

Operation request from: Everyone (Active Directory)

Filtering conditions: Not specified. 

The conditions of the above are set to Workflow starts upon a request for changes to and this is set to the TestVA

I have dragged the approval activity in to the work flow and set myself as the approver. However i am never seeing an approval request come through via email or in the WI. What am i ding wrong? 

ARS version is 7.4

Many thanks

Criag