Gitto, it is thematic but parsing it is not essential for the PDM. I finished the puzzle before managing to parse it.
There are a couple of others that I haven't so far managed to parse.
There is also one clue where an abbreviation is wrongly indicated since it's not supported in the latest Chambers. Alternatively, the setter has used a synonym for an alternative abbreviation, but I find that unacceptable. I'm referring to the fifteenth across clue, the one with 'Macron'.