diff --git a/core/src/ParaGridIO_Xios.cpp b/core/src/ParaGridIO_Xios.cpp
index d96b894a4..f9e27e19a 100644
--- a/core/src/ParaGridIO_Xios.cpp
+++ b/core/src/ParaGridIO_Xios.cpp
@@ -78,6 +78,14 @@ ModelState ParaGridIO::getModelState(const std::string& filePath, ModelMetadata&
 #endif
 }
 
+ModelState ParaGridIO::readForcingTimeStatic(
+    const std::set<std::string>& forcings, const TimePoint& time, const std::string& filePath)
+{
+    ModelState state;
+    throw std::runtime_error("XIOS implementation of readForcingTimeStatic incomplete"); // TODO-JGW
+    return state;
+}
+
 /*!
  * @brief Writes the ModelState to a given file location from the provided
  * model data and metadata.
diff --git a/core/src/include/ParaGridIO_Xios.hpp b/core/src/include/ParaGridIO_Xios.hpp
index 02fbd2e44..9fb2847c9 100644
--- a/core/src/include/ParaGridIO_Xios.hpp
+++ b/core/src/include/ParaGridIO_Xios.hpp
@@ -72,6 +72,9 @@ class ParaGridIO : public ParametricGrid::IParaGridIO {
      */
     void writeDiagnosticTime(
         const ModelState& state, const ModelMetadata& meta, const std::string& filePath) override;
+
+    static ModelState readForcingTimeStatic(
+        const std::set<std::string>& forcings, const TimePoint& time, const std::string& filePath);
 };
 } /* namespace Nextsim */
 
diff --git a/core/test/ConfigOutput_test.cpp b/core/test/ConfigOutput_test.cpp
index facbc8e57..c912ece7e 100644
--- a/core/test/ConfigOutput_test.cpp
+++ b/core/test/ConfigOutput_test.cpp
@@ -1,7 +1,7 @@
 /*!
  * @file ConfigOutput_test.cpp
  *
- * @date 24 Sep 2024
+ * @date 31 Oct 2024
  * @author Tim Spain <timothy.spain@nersc.no>
  */
 
@@ -21,8 +21,8 @@
 #include "include/ModelComponent.hpp"
 #include "include/ModelMetadata.hpp"
 #include "include/ModelState.hpp"
-#include "include/NextsimModule.hpp"
 #include "include/NZLevels.hpp"
+#include "include/NextsimModule.hpp"
 #include "include/gridNames.hpp"
 
 #include <ncDim.h>
@@ -144,7 +144,7 @@ TEST_CASE("Test periodic output")
             hsnow += hourIncr;
             ModelState state;
 
-            ido.outputState(meta);
+            ido.outputState(meta); // FIXME-JGW: XIOS impl fails here
             meta.incrementTime(Duration(3600.));
         }
     }
diff --git a/core/test/ParaGrid_test.cpp b/core/test/ParaGrid_test.cpp
index a840fa14b..7a19d7715 100644
--- a/core/test/ParaGrid_test.cpp
+++ b/core/test/ParaGrid_test.cpp
@@ -255,7 +255,7 @@ TEST_CASE("Write and read a ModelState-based ParaGrid restart file")
 #ifdef USE_MPI
     ModelMetadata metadataIn(partitionFilename, test_comm);
     metadataIn.setTime(TimePoint(dateString));
-    ModelState ms = gridIn.getModelState(filename, metadataIn);
+    ModelState ms = gridIn.getModelState(filename, metadataIn); // FIXME-JGW: XIOS impl fails here
 #else
     ModelState ms = gridIn.getModelState(filename);
 #endif
@@ -520,14 +520,11 @@ TEST_CASE("Test array ordering")
     std::set<std::string> fields = { fieldName };
     TimePoint time;
 
-#ifdef USE_XIOS
-    throw std::runtime_error("XIOS implementation incomplete"); // TODO-JGW
-#else
+    // FIXME-JGW: XIOS impl fails here
     ModelState state = ParaGridIO::readForcingTimeStatic(fields, time, inputFilename);
     REQUIRE(state.data.count(fieldName) > 0);
     index2d = state.data.at(fieldName);
     REQUIRE(index2d(3, 5) == 35);
-#endif
 }
 
 #ifdef USE_MPI
@@ -610,7 +607,8 @@ TEST_CASE("Check if a file with the old dimension names can be read")
     metadata.localExtentX = 1;
     metadata.localExtentY = ny;
     metadata.setTime(TimePoint(dateString));
-    ModelState ms = gridIn.getModelState(inputFilename, metadata);
+    ModelState ms
+        = gridIn.getModelState(inputFilename, metadata); // FIXME-JGW: XIOS impl fails here
 #else
     ModelState ms = gridIn.getModelState(inputFilename);
 #endif
diff --git a/physics/src/modules/AtmosphereBoundaryModule/ERA5Atmosphere.cpp b/physics/src/modules/AtmosphereBoundaryModule/ERA5Atmosphere.cpp
index 7f30d4a29..c8afe29a2 100644
--- a/physics/src/modules/AtmosphereBoundaryModule/ERA5Atmosphere.cpp
+++ b/physics/src/modules/AtmosphereBoundaryModule/ERA5Atmosphere.cpp
@@ -64,9 +64,6 @@ void ERA5Atmosphere::update(const TimestepTime& tst)
     std::set<std::string> forcings
         = { "tair", "dew2m", "pair", "sw_in", "lw_in", "wind_speed", "u", "v" };
 
-#ifdef USE_XIOS
-    throw std::runtime_error("XIOS implementation incomplete"); // TODO-JGW
-#else
     ModelState state = ParaGridIO::readForcingTimeStatic(forcings, tst.start, filePath);
     tair = state.data.at("tair");
     tdew = state.data.at("dew2m");
@@ -80,7 +77,6 @@ void ERA5Atmosphere::update(const TimestepTime& tst)
     emp = 0; // FIXME get E - P data
 
     fluxImpl->update(tst);
-#endif
 }
 
 void ERA5Atmosphere::setFilePath(const std::string& filePathIn) { filePath = filePathIn; }
diff --git a/physics/src/modules/OceanBoundaryModule/TOPAZOcean.cpp b/physics/src/modules/OceanBoundaryModule/TOPAZOcean.cpp
index a849b4054..016f00749 100644
--- a/physics/src/modules/OceanBoundaryModule/TOPAZOcean.cpp
+++ b/physics/src/modules/OceanBoundaryModule/TOPAZOcean.cpp
@@ -63,9 +63,6 @@ void TOPAZOcean::updateBefore(const TimestepTime& tst)
     // TODO: Get more authoritative names for the forcings
     std::set<std::string> forcings = { "sst", "sss", "mld", "u", "v" };
 
-#ifdef USE_XIOS
-    throw std::runtime_error("XIOS implementation incomplete"); // TODO-JGW
-#else
     ModelState state = ParaGridIO::readForcingTimeStatic(forcings, tst.start, filePath);
     sstExt = state.data.at("sst");
     sssExt = state.data.at("sss");
@@ -79,7 +76,6 @@ void TOPAZOcean::updateBefore(const TimestepTime& tst)
         TimestepTime());
 
     Module::getImplementation<IIceOceanHeatFlux>().update(tst);
-#endif
 }
 
 void TOPAZOcean::updateAfter(const TimestepTime& tst)