EWR3 Grid - EPSG:10851

WKT

PROJCS["EWR3_Grid", 
	GEOGCS["EWR3-IRF", 
		DATUM["EWR3_Intermediate_Reference_Frame", 
			SPHEROID["GRS_1980", 6378137.0, 298.257222101]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 192519.9715], 
	PARAMETER["False_Northing", 146942.6806], 
	PARAMETER["Central_Meridian", -0.9], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", 51.95], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["EWR3_Grid", 
	BASEGEOGCRS["EWR3-IRF", 
		DATUM["EWR3_Intermediate_Reference_Frame", 
			ELLIPSOID["GRS_1980", 6378137.0, 298.257222101]], 
		PRIMEM["Greenwich", 0.0], 
		CS[ellipsoidal, 2], 
		AXIS["Latitude (lat)", north, 
			ORDER[1]], 
		AXIS["Longitude (lon)", east, 
			ORDER[2]], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	CONVERSION["Transverse_Mercator", 
		METHOD["Transverse_Mercator"], 
		PARAMETER["False_Easting", 192519.9715], 
		PARAMETER["False_Northing", 146942.6806], 
		PARAMETER["Central_Meridian", -0.9], 
		PARAMETER["Scale_Factor", 1.0], 
		PARAMETER["Latitude_Of_Origin", 51.95]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["EPSG", "10851"]]

Data from @esri/proj-codes

{
  "wkid": 10851,
  "latestWkid": 10851,
  "gcsWkid": 10849,
  "macro": "PE_PCS_EWR3_GRID",
  "name": "EWR3_Grid",
  "wkt": "PROJCS[\"EWR3_Grid\",GEOGCS[\"EWR3-IRF\",DATUM[\"EWR3_Intermediate_Reference_Frame\",SPHEROID[\"GRS_1980\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",192519.9715],PARAMETER[\"False_Northing\",146942.6806],PARAMETER[\"Central_Meridian\",-0.9],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",51.95],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"EWR3_Grid\",BASEGEOGCRS[\"EWR3-IRF\",DATUM[\"EWR3_Intermediate_Reference_Frame\",ELLIPSOID[\"GRS_1980\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433]],CONVERSION[\"Transverse_Mercator\",METHOD[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",192519.9715],PARAMETER[\"False_Northing\",146942.6806],PARAMETER[\"Central_Meridian\",-0.9],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",51.95]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"EPSG\",\"10851\"]]",
  "description": "EWR3 Grid",
  "authority": "EPSG",
  "version": "12.008(13.6.0)",
  "deprecated": "no",
  "areaname": "UK - Oxford to Cambridge",
  "extent": {
    "slat": 51.7,
    "nlat": 52.33,
    "llon": -1.43,
    "rlon": 0.27
  }
}