Streaming Best Available Bug
Found an issue where the following became present in MarketBook:

{'size': 0, 'price': 0}

Tried to recreate but I can't looks like it was due to receiving an update to delete a price when it was not present in the cache.
diff --git a/betfairlightweight/__init__.py b/betfairlightweight/__init__.py
index d9a6b0c..43a81be 100644
--- a/betfairlightweight/__init__.py
+++ b/betfairlightweight/__init__.py
@@ -5,5 +5,5 @@ from .filters import MarketFilter, StreamingMarketFilter, StreamingMarketDataFil
 
 
 __title__ = 'betfairlightweight'
-__version__ = '0.9.9'
+__version__ = '0.9.10'
 __author__ = 'Liam Pauling'
diff --git a/betfairlightweight/utils.py b/betfairlightweight/utils.py
index b69d7b1..041460d 100644
--- a/betfairlightweight/utils.py
+++ b/betfairlightweight/utils.py
@@ -102,5 +102,6 @@ def update_available(available, book_update, deletion_select):
                     updated = True
                     break
 
-        if not updated:
+        if not updated and book[deletion_select] != 0:
+            # handles betfair bug, http://forum.bdp.betfair.com/showthread.php?t=3351
             available.append(book)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 392858b..f21b9e3 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -144,6 +144,14 @@ class UtilsTestUpdateAvailable(unittest.TestCase):
         update_available(current, book_update, 2)
         assert current == expected
 
+        # tests handling of betfair bug, http://forum.bdp.betfair.com/showthread.php?t=3351
+        book_update = [[2, 0, 0], [1, 1.01, 9835.74], [0, 1.02, 1126.22]]
+        current = [[1, 1.01, 9835.74], [0, 1.02, 1126.22]]
+        expected = [[1, 1.01, 9835.74], [0, 1.02, 1126.22]]
+
+        update_available(current, book_update, 2)
+        assert current == expected
+
     def test_update_available_new_remove(self):
         book_update = [[27, 0]]
         current = [[27, 0.95], [13, 28.01], [1.02, 1157.21]]
['betfairlightweight/utils.py', 'tests/test_utils.py', 'betfairlightweight/__init__.py']