Very impressed with the advice you are giving on your website so could I ask a little for myself?
I live in a barn converted about 20 years ago where some of the internal walls have been lined with modern building block and what appears to be a concrete based render (not plaster) with cavities whilst other areas display the original stone. There is no damp problem. We now intend to decorate the rendered walls (not the stonework) which appear to already have been painted with emulsion. Is it Ok to use Dulux Diamond matt? Or what do you suggest?
Thanking you in anticipation