I should add we have a terracotta roof and the gutters are deep ocean (hoping to paint them)

We have dulux chanson on ensuite walls paired with white cabinetry and trims. https://www.dulux.com.au/colour/chanson Aerobus= slightly darker or Miller mood = slightly lighter

Looking for a light grey paint for a new build inside walls any suggestions

Why don't you engage a Dulux Colour consultant to pay you a visit? It is impossible to make sound recommendations from digital photos as there is so much variation with cameras, screens, natural day light and atificial light. There are about 4600 Dulux colours with only about 10% available at your hardware store as colour chips so a Dulux colour consultant can help you find the perfect colour and organise an A4 sized sample. https://www.dulux.com.au/services/colour-design-service/overview?gclid=CjwKCAjw4NrpBRBsEiwAUcLcDGDFlYcONZGEWBc865ndCnsVmwd-CDa84Ise2d5rwdvtwOsVBT_kphoCzVcQAvD_BwE&cid=ppc|google|dulux.com.au_main||||||||||DCDS+-+Brand+%28Australia+Wide%29+-+EM+%28DLX%29|||Brand+-+Colour+Consultant+EM|&ef_id=CjwKCAjw4NrpBRBsEiwAUcLcDGDFlYcONZGEWBc865ndCnsVmwd-CDa84Ise2d5rwdvtwOsVBT_kphoCzVcQAvD_BwE:G:s&s_kwcid=AL!4713!3!335581778534!e!!g!!dulux%20colour%20consultant Best of luck, Dr Retro of Dr Retro House Calls