Good fun I thought. Definitely enough references to constitute a theme without feeling forced. FOI was 16a. NW corner held out until the end. Sounds like I did exactly the same as Brendan with the ending of 15d but 23a was clear and I knew the reference in 25a fortunately. I think I’m missing something in 6d as it doesn’t seem particularly cryptic?
4d - This puzzled me for a while too, I kept trying to find a 3 letter word 'complain' to put around 'one' when it's actually much more straightforward with "about" being a reversal indicator and then the definition is the last 4 words.