Pddco: Nice idea! I'd long since forgotten that the Journels were available. I did have a couple that took me right back to Strowger days but I fear they have been disposed of by the powers that be!
iniltous: I believe the pdfs you included above have pretty much answered my question diagramatically, ie its a (presumably new) Line Access Gateway that does the functions that I was quering. So thanks.
Thanks for being intrigued. I wouldn't have found what Home Phone Standard was without your enquiry. That it's just a latest name for packaging the PDPL via SOTAP for Analogue product. Thanks to all the contributors here for that.