https://thumbsnap.com/uQryipKc
To answer my own question, in a thread from last year about Houx on Pistonheads I've found a small part of the new map. Not the complete thing, but enough to see roughly how the numbering works.
Row 47 on the new map is the same as row 47 on the old one.
Row 48 on the new map is row 46 on the old one.
Row 46 on the new map is row 45 on the old one.
Row 45 on the new map is row 44 on the old one.
....
....
....
Row 29 on the new map is row 28 on the old one.
So my whereabouts are now pretty much determined, but if anyone could source the complete map, I'd still be very grateful!!