Now counting the number of factories and checking the number of tags covered by a filter using tagged inputs against this. This currently fails, which is expected.
Fix bug where the expansion of a deferral node into its subtree was losing any filters / tags applied to it - the expansion now has a root that is an artificial node that preserves the properties of the original deferral node. Also removed the early-detection preconditions on the filters , as these were causing test failures - definitely related to the tests not taking into account that deferrals don't have to be expanded at maximum strength - and also possibly because of some genuine bug (or perhaps another test bug). Either way, I'm calling it a day...