How much to remove part of chimney breast?

Catbells

Hi. We have a chimney breast in a downstairs room which doesn't continue all the way up through the room above so it has no support function. We want to retain it but knock the central part out and put two large cupboards there. When I mentioned this to the builder he raised his eyebrows and said knocking out and removing central chimney breast would be expensive. He hasn't come back with a quote yet as there are other jobs we need doing too. Does anyone know how much this should cost including building in the cupboards? This would be helpful when he does come back with the quote. Thanks. We live on London/Herts borders.