No reason to be afraid feardorcha.
A lesser house will usually attract a resaonable response.
You could box clever and design the house as a phased development over time.
However while you may save on the initial build costs of the house proper, main items of expense such as the entrance, driveway, parking apron, foul sewage runs and treatment system and surface water disposal / attenuation system may all be asked for as part of Phase I.
FWIW
ONQ
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All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.