Now that is a very good question! Assuming you want the building you are applying for now and then 1000sqm of PD then you have to be very careful about your timescales as the Full Planning Permission my restrict your future PD rights, so this is how my boss just explained it would work in your favour.Just thinking out loud.
Would I be better to go for full planning this time with a view to keeping PD rights up my sleeve for future
1. Apply for full PP for your building.
2. At any time after this has been submitted (but before the 3 year build period has expired) apply for you PD buildings.
3. Ensure you build your PD buildings before starting work on the Full PP building.
The basis of this is that even if the councildoes restrict your PD rights as part of the full PP that does not come into force until you enact (start) that work. You can then buld your 1000sqm worth of PD buildings and that has no impact on the full PP building. Just remember to start that within the 3 years as renewing that permission would be much harder once the PD buildings were up.