Well after suffering issues with damp located on my exterior wall near my air vent we have started to strip back to the brick ready to tank the interior of the wall. When doing this we have found what looks like a bodged attempt of filling up the wall, where I believe an external door used to be. We're now just unsure what to do about it, we've been advised to block up the air vent as this was apparently only left because due to their being a back boiler installed, we changed this and installed a new boiler years ago so were planning to brick this up. But am now not sure if this is the best thing to do or how to go about it, any advise helpful!