Ideally have them put in shelves that can be adjusted (holes down the sides that you put those plugs into.) That way you can make the shelves varying heights that best suits what you want yo put in there. I did this, and I have one tall shelf for high cereal packets and other smaller shelves that just accommodate two tins on top of each other, plus another shelf that is just right for my storage containers. That way you make the best use of the space.

an easier way to "avoid voids" would be to have a simple L shaped 50cm deep counter on two sides with a small drop in sink and standard wall cabinets with open shelves above and below ...the extra dotted line on the 311 side of my plan shows a tall x 15cm deep x 79cm wide open shelf ideal for numerous cans, bottles and packetsomitting doors would save space (and cost) and give much easier access to the corners and any cabinet maker should be able to produce this arrangement by producing several custom sized base cabinets (similar to this plan) with standard sized wall cabinets and extra adjustable shelves

if the space is at least 4m x 4m then something like this should work but as soon as you have more precise measurements we can make adjustments and maybe make space for a washing machine inside as well? the tall shallow pantry cabinets could be custom made or if you have access to IKEA or similar there are flat pac suitable cabinets but they must le less than 40cm deep to allow enough walking space with a 90cm island OR the side cabinets could be deeper base cabinets plus more wall cabinets and the island narrower eg a 75cm wide island and 60cm deep side cabinet with walkway adjusted to suit and/or the parts of the island could be like a table so that stools could fit under completely and be out of the walkways when not needed

The overal design, layout and zoning of the house is really quite good - a separate master zone looking onto a pool and a secondary bedroom zone with a decent entry - however the kitchen scale & amenity is arguably the weak point & undersized for what people want/need these days....as Kate mentioned I'd consider a 2nd living area really practical in growing family situations but i'd also see there are options of how to potentially achieve here not being in with the kitchen/dining say by utilising the outdoor living area (with blinds?) or even look at the garage as a proper rumpus/mpr space if that was needed....comes down to balancing personal priorities/needs etc..