See here - golden-lane-guidelines-spd.pdf
Not surprised City of London has quietly removed these from their website given repeated ignoring of this document over recent years.
For example, not quite sure how COLPAI and Denizen fit with “no new buildings, infilling, removals or extensions should be introduced which would be detrimental to the integrity of the Estate as a whole. The relevant planning authority should, therefore, take into account the significance of the Estate’s setting to its special architectural interest when considering any developments on the immediate boundary of the estate” !
Thanks Paul, that's really helpful — I sense (and sympathise) with your frustration…