Merge pull request #172 from Financial-Times/leggsimon-patch-2

better explain the parity error

Makefile

@@ -96,7 +96,7 @@ ifneq ($(CIRCLE_BUILD_NUM),)
 ifneq ($(shell grep -s -Fim 1 n-ui bower.json),)
 # versions in package.json and bower.json are not equal
 ifneq ($(shell awk '$$1 == "\"version\":" {print $$2}' bower_components/n-ui/.bower.json | sed s/,//),$(shell awk '$$1 == "\"version\":" {print $$2}'  node_modules/@financial-times/n-ui/package.json | sed s/,//))
-	$(error 'Projects using n-ui must maintain parity between versions. Rebuild without cache and update your bower.json and package.json if necessary')
+	$(error 'Projects using n-ui must maintain parity between versions. Rebuild without cache and update your bower.json and package.json if necessary. If this error persists make sure that the n-ui build succeeded in publishing a new version to Bower and NPM.')
 endif
 endif
 endif