Hello Mikael, sorry i write late i wast at office :)
There are a solution about your issue. I hope this help,
First of all your GUP have 2 address therefore your update policy should be with ip addres not machine name. Cause DNS can send ip packages to another Ip address. Therefore will be problem with connection. Change your Live update polic for GUP Ip address (10.1.252.1)
this will help your last question :)
SEP Manager And GUP must not to same Ip addressi For example my SEP Manager 10.20.30.40 But my gup can be 10.20.50.120 (255.255.255.0) package transferin is important when subneting.
And your another posts if you need more live update policy and more rules you can create second group. and you can give rules for changes. For example If client ip address change go to Internet for updates, or if client cannot access to sep manager use this update policy etc.
I have a article about how to create second group (out of office rule)
I hope it will be help you: )
https://www-secure.symantec.com/connect/articles/how-create-out-office-locations-rule
Best Regards.
Fatih