COMPOUNDCRS["SMITB20 Grid + ODN height",
    PROJCRS["SMITB20 Grid",
        BASEGEOGCRS["SMITB20-IRF",
            DATUM["SMITB20 Intermediate Reference Frame",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            ID["EPSG",10272]],
        CONVERSION["SMITB20-TM",
            METHOD["Transverse Mercator",
                ID["EPSG",9807]],
            PARAMETER["Latitude of natural origin",50.75,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8801]],
            PARAMETER["Longitude of natural origin",-3.85,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8802]],
            PARAMETER["Scale factor at natural origin",1,
                SCALEUNIT["unity",1],
                ID["EPSG",8805]],
            PARAMETER["False easting",110693.666,
                LENGTHUNIT["metre",1],
                ID["EPSG",8806]],
            PARAMETER["False northing",102089.2943,
                LENGTHUNIT["metre",1],
                ID["EPSG",8807]]],
        CS[Cartesian,2],
            AXIS["(E)",east,
                ORDER[1],
                LENGTHUNIT["metre",1]],
            AXIS["(N)",north,
                ORDER[2],
                LENGTHUNIT["metre",1]]],
    VERTCRS["ODN height",
        VDATUM["Ordnance Datum Newlyn"],
        CS[vertical,1],
            AXIS["gravity-related height (H)",up,
                LENGTHUNIT["metre",1]]],
    USAGE[
        SCOPE["Engineering survey and topographic mapping for railway applications."],
        AREA["United Kingdom (UK) - on or related to the rail route from Okehampton to Penstone."],
        BBOX[50.65,-4.11,50.86,-3.6]],
    ID["EPSG",10276]]