Had a couple sticky points whilst doing it so far but managed to resolve them myself with a bit of careful examination, head scratching, reading etc but have got somewhere that's baffled me. Think i might have to take the left hand portion of the dash off, which will be a royal smegpot.
Got so far as pulling the old cable and connector through (with string tied tightly onto it just behind the wider portion of the connector, so the new one will come through easy