@Miles80 

there're many ways to go at this task.  i'm not an expert and my advice might not be the best, but it has worked for me so far.  For 30 cam, if all the cables from every cameras or access points recieving the video footage via wifi are long enough to join in one place.  Vigi nvr 4032, coupled with 48 poe ports managed switch, is the set-up to keep it simple physically and technically.  This way spare u the complication of multi-vlans scenario.  

it's possible to have multiple nvrs in the same subnet or vlan, but the nvr will keep tring to adopt the camera that got hooked up to the other nvr.  You easily got confused and lost as to which nvr and camera u work with.  it's really frustrating when mistake happened because u lose focus.  anyway, u can have two separate systems one for inside and one for outside.

I feel like i am way over my head for non-professional giving tips ontechnical level.  I only set up for my own buildings 20+ places almost 4k units.  u should wait forthe real network professional technician who is kind enough to spend time answer your question.

i answered this coz no one want to help.  that's it. dont blame me if u think my method is a bad idea.

peace