Brendan - the preamble says that you have to alter 6 across clues via a 'thematic change' before solving. Could this apply to 27a?
The preamble also says that 3 down clues are wordplay only. 25d? You have the first letter, clued by the first word in the clue. The 'jewish date' is an abbreviation, in the same way as 'BC' or 'AD' is for Christians.
23d is not an anagram, and has an extra letter in the wordplay. the definition is the last 2 words.