If I add a quote/estimate to the new customer then it show's up in the portal.
As a test, try running this one line script after making the change to the yes/no field:
Refresh WIndow [Flush cached join results]
Does that cause your portal to update correctly to show this change?
If so, a simple change to the relationship used for your portal can fix this issue.
I tried adding that code but it still hasn't done anything.
01. Is Home (i assume is layout name) represent data from another table ? if so what is the relationship you make with customers and home screen's table ?
02. did you create calculation to portal to show the data if "Yes" (i think you have doen this,but its good dubble check)
03. I suggest phils method, just adding little bit steps on to that go to layout mood and select the yes/no field and right click select the script triggers and select onobjectsave. after map the script of refresh to that task.
Need more details about what you have set up that isn't working for you.
Are you using a filtered portal?
If so, what is the filter expression?
And whether you are using a filter or not, what is the relationship on which your portal is based?