I would go with both of the previous posts. Whoever wrote that specification doesn't know what they are doing, and it's likely that the pathway has been raised up outside.
When you treat rising damp, you hack off the plaster inside, drill and inject the silicone cream in to the mortar course, not the brickwork, apply a cement render with a waterproofer in it making sure it's washed sand not building sand, and then plaster as per normal. You don't leave the old plaster on there, as it could take a year to dry out, and the wall will stay damp until it does. Furthermore, if you leave the plaster there, then the damp can creep up and over the chemical DPC via the old plaster itself. Their last section on sound plaster is a contradiction, because if any plasters damp, then it need treating, and if it's not in the affected area, then it won't be damp.
Points 1 to 4 need dealing with, but without further indication and pictures of the outside, then it's difficult to asses, but I cant see them costing too much.
If you haven't paid them yet, then don't, and if you have, get them back in, and tell then to get it sorted, otherwise you want a refund.