diff --git a/tests/cmd_declination_conv_proj_bug.out b/tests/cmd_declination_conv_proj_bug.out
index edf5bb89..24982607 100644
--- a/tests/cmd_declination_conv_proj_bug.out
+++ b/tests/cmd_declination_conv_proj_bug.out
@@ -1,5 +1,5 @@
-./cmd_declination_conv_proj_bug.svx:9: info: Declination: -3.5dg @ 2005-12-15, grid convergence: 0.8dg
- *declination auto 97480 72608 225
+./cmd_declination_conv_proj_bug.svx:16: info: Declination: -3.5dg @ 2005-12-15, grid convergence: 0.8dg
+ *declination auto 562696.24 6000557.63 225
 
 Removing trailing traverses...
 
diff --git a/tests/cmd_declination_conv_proj_bug.svx b/tests/cmd_declination_conv_proj_bug.svx
index a1d490c0..71f65e35 100644
--- a/tests/cmd_declination_conv_proj_bug.svx
+++ b/tests/cmd_declination_conv_proj_bug.svx
@@ -1,14 +1,21 @@
 ; pos=yes warn=0
-; Reduced testcase posted by Patrick Warren to the mailing list
-; The convergence was wrong by 90 degrees with PROJ < 9.3.0.  Survex 1.4.6
-; works around the problem.  Also if *cs out was after *declination auto
-; a grid convergence of 0 degrees was used - Survex 1.4.6 calculates the
-; convergence lazily which happens when we read a compass reading, and
-; gives an error if the output coordinate system hasn't been set by then.
-*cs OSGB:SD
-*declination auto 97480 72608 225
+; Based on reduced testcase posted by Patrick Warren to the mailing list.
+;
+; The input coordinate system has been changed from OSGB:SD as that was giving
+; different output on Linux and macOS depending whether the datum grid is
+; installed.
+;
+; The convergence value was 90-v instead of v with PROJ < 9.3.0.  Survex 1.4.6
+; works around the problem.
+;
+; Also if *cs out was after *declination auto a grid convergence of 0 degrees
+; was used - Survex 1.4.6 calculates the convergence lazily which happens when
+; we read a compass reading, and gives an error if the output coordinate system
+; hasn't been set by then.
+*cs EPSG:25830
+*declination auto 562696.24 6000557.63 225
 *cs out EPSG:3042
 *date 2005.12.15
-*fix 1 97480 72608 225
+*fix 1 562696.24 6000557.63 225
 *data normal from to tape compass clino
 1 2 25.0 000 0 ; due north, magnetic