diff --git a/codelists/models.py b/codelists/models.py
index cee50a85..6ae54674 100644
--- a/codelists/models.py
+++ b/codelists/models.py
@@ -637,11 +637,17 @@ def table_with_fixed_headers(self, include_mapped_vmps=True):
                         prev_to_vmp_mapping[previous_vmp] = vmp
                 else:
                     # if the vmp wasn't in the codelist codes, then the mapped previous one
-                    # must be
+                    # must be. We're mapping in a code that is subsequent to one in the current codelist.
                     assert previous_vmp in codes
-                    # and it must be in the mapping of vmp to previous that we'll look it up in
-                    # later
-                    assert previous_vmp in vmp_to_prev_mapping
+
+                    # The mapped code must be in ONE of the direct mappings
+                    # It's either previous to a current code (and in vmp_to_prev_mapping), or previous to
+                    # another previous code of current code,in which case it will be in the
+                    # prev_to_vmp_mapping
+                    if previous_vmp not in vmp_to_prev_mapping:
+                        assert previous_vmp in prev_to_vmp_mapping
+                        # add the mapped VMP into the mapping so we can add in the description
+                        vmp_to_prev_mapping[vmp] = prev_to_vmp_mapping[previous_vmp]
                     # mapping a code in the codelist to a new code that supercedes it
                     subsequent_vmps_to_add.add(vmp)
 
diff --git a/codelists/tests/views/test_version_download.py b/codelists/tests/views/test_version_download.py
index 6b13fd6e..af2ea6b0 100644
--- a/codelists/tests/views/test_version_download.py
+++ b/codelists/tests/views/test_version_download.py
@@ -130,10 +130,16 @@ def test_get_with_mapped_vmps_more_than_one_step_distant(
     # create a previous mapping for one of the dmd codes
     Mapping.objects.create(id="10514511000001106", vpidprev="999")
     # create a previous mapping for this previous code
-    # create a new mapping for one of the dmd codes; neither of these
-    # codes are in the codelist, but 777 needs to be mapped in as a previou
+    # create two more mapping for one of the dmd codes; neither of these
+    # codes are in the codelist, but 777 and 666 need to be mapped in as a previous
     # code to 10514511000001106, which is in the codelist
     Mapping.objects.create(id="999", vpidprev="777")
+    Mapping.objects.create(id="777", vpidprev="666")
+
+    # create some new mappings for one of the dmd codes
+    Mapping.objects.create(id="AAA", vpidprev="10514511000001106")
+    Mapping.objects.create(id="BBB", vpidprev="AAA")
+    Mapping.objects.create(id="CCC", vpidprev="BBB")
 
     rsp = client.get(dmd_version_asthma_medication.get_download_url())
     data = rsp.content.decode("utf8")
@@ -141,6 +147,10 @@ def test_get_with_mapped_vmps_more_than_one_step_distant(
         ["code", "term"],
         ["10514511000001106", "Adrenaline (base) 220micrograms/dose inhaler"],
         ["10525011000001107", "Adrenaline (base) 220micrograms/dose inhaler refill"],
+        ["666", "VMP previous to 10514511000001106"],
         ["777", "VMP previous to 10514511000001106"],
         ["999", "VMP previous to 10514511000001106"],
+        ["AAA", "VMP subsequent to 10514511000001106"],
+        ["BBB", "VMP subsequent to AAA"],
+        ["CCC", "VMP subsequent to BBB"],
     ]