We have a detached house and next door boundary is within 2 metres. They have a side window with obscure glass. We want to extend by around 2.5 metres single story within permitted development. We asked them to confirm no objection when we request permission from the freeholder before plans are drawn. They have objected as the new wall will be in front of their side window. Will they be able to object to the council also if it is within permitted development?. We bought the house 6 months ago and they have house up for sale.