Damp/ condensation in open fireplace

[emmmadorset]

Hi there, we have an open fireplace in our kitchen (1930s detached). The chimneys have been removed. As you can see from the photos, we have an issue with damp and condensation. We've had a damp specialist round who wants to inject a chemical dpc into the wall, install two air bricks, brace the chimney opening, then add a dpm on the internal wall and plasterboard in preparation for a new kitchen, which includes blocking up the opening. I have attached photos of the fireplace, the external, an annotated photo of where the damp was identified with damp meter (pink), and where the company want to add a dpm and then plasterboard (yellow). Is this overkill? Is there a cheaper alternative that will still stop future issues of damp presenting in the kitchen?