question

However, in the future I also want to add more panels (7kw) using the 
MPPT DC-DC modules charging the batteries directly. If it is sunny and 
both sets of panels are producing max power, do I then need to have 
12000VA?

No, "factor 1.0" applies only to the AC coupled PV inverter.

Also, the following post https://www.victronenergy.com/live/ac_coupling:start
 mentions that for 1.5kw of panel you require 100 amps at 48V which 
would imply the ability to take 4.8kw. Does that mean 3kw requires 200? ?

Yes, that is suggested size of LFP battery when PV inverter is AC coupled.

Thank you both @Andy156 and @MarekP

I have updated that originally linked manual with the answers;

4 Requirement of adding DC-Coupling - MPPT Solar Chargers

There is no Factor 1.0 limit that applies for DC coupled PV through a Victron MPPT. Nor is there a specific minimum amount of battery storage capacity, though please follow battery manufacture specifications for maximum charge rates. A rule of thumb is C10 (10% of Ah capacity in A) for lead acid batteries, and C2 (50% of Ah capacity in A) for lithium batteries.

3.1 Lead batteries

1 kWp installed PV power requires approximately 5kWh of lead acid battery:

100 Ah at 48 Vdc

200 Ah at 24 Vdc

400 Ah at 12 Vdc

Each additional 1 kWp of AC PV will require an additional proportional 5 kWh increase in lead acid battery storage.

3.2 Lithium batteries

1,5 kWp installed AC PV power requires 4.8 kWh of battery storage:

100 Ah at 48 Vdc

200 Ah at 24 Vdc

400 Ah at 12 Vdc

Each additional 1.5 kWp of AC PV will require an additional proportional 4.8 kWh increase in battery storage.