Bloody clunk

So, 2018 BRZ TS manual. Got it second hand with nearly 100 000 km on the clock.

Everything seems OK enough, got my growing to do list of minor fixes coming along.

Booked in with a subie garage first thing in the morning next week so they can hopefully diagnose, but reaching out in case someone knows already.

Basically, after start up, whether I wait for the blue temp light to go or not, when I roll out of the driveway, when the car changes pitch /incline NOT when the suspension is compressing or rebounding I get a pop/clunk that I can just feel and hear from the inside or outside. I'll get a couple at the start and then not for the rest of the drive. It feels like it is coming from the engine.

I have tried harsh braking & accelerating, as well as slalom really harsh side to side turning, and deliberately rolling over bumps and the noises can't be replicated.

I've checked all the suspension & steering links, strut tower bars and can't see anything, thinking maybe engine mounts, but then I should be able to replicate it later in the drive, but I can't.