Morning all,
On the easier side I thought. The long ones went in early. I confidently put another three letter acronym in for 19a which I think works just as well as the intended answer and that held me up. I also know an old writer that fits with all but one of the crossers in 12a which I spent far too long trying to make work!
Brendan, on your question, I agree that as this is a prize, nudges when asked for may be preferable to unsolicited hints.