I actually thought it might have been the AO nodes, so I disabled the one on the fireplace and it did nothing so I moved on. The full scene is actually quite complex and every one of the materials has an AO node because it gives the effect that I want so I would rather not remove them but I will play about with the distance as you suggested.
I am still running 2.8 as this is an important project and I don’t trust the newer builds until they have been officially released but I will have a play about with them with a safe save – thanks for the tip.
At least we now know the issue, and I found a temporary work around which is to move the domain back slightly once it has baked , which moves the intersecting fire away from the fireplace. I did a test animation and it works.
Thanks for the help 🙂 Much appreciated!
