Waldorf Grange 50 garage opening height 2400mm

We are ready to sign up for the Waldorf Grange 50 with all the bells and whistles which will come in around 600-650 k.We have come across one major issue which is quite frustrating to say the least. We do love this home and it ticks all the boxes and suits our block perfectly. I have a work van which needs to be garaged and needs a garage opening height of 2400 mm to fit in. We have discovered the standard opening is 2285 mm and have requested the opening be made to suit by having one row of brick less to make the opening slightly bigger but have been informed this cannot be done due to the room above the garage. So we have then asked if the slab could be dropped slightly by 120 mm to accommodate the work van but again were told it cannot be done. I have asked if the floor in the room above the garage be raised slightly to accommodate the raising of the garage ceiling but they will not do it. Is this the case Porter Davis ?? my requests don't seem so unreasonable do they???

Please Porter Davis if you could respond with hopefully an easy solution to my problem I welcome any suggestions you may have apart from the obvious which is selling my van ....loI ( it is a custom van fitted out with specialized equipment so this is not an option unfortunately) I'm left with no choice but to look for another builder If my issue cannot be resolved for this last little hiccup which is not what I'm wanting to do... please try and help as this will be our 3rd Porter Davis home we have built.

Many Thanks Danny