Hi folks, thanks for your concerns & thoughts!

In case I wasn’t clear in my OP, these issues are so far related to the aftermarket adapters and the Feathertouch focuser, and Joshua is correct in saying that small errors can really add up when parts aren’t actually square. (and maybe, possibly with the Tak reducer too).
Stefan has just advised that the new flattener adapter is ready, and that the Tak 67 flattener is in itself a beautiful, well made piece of engineering! (Very high praise indeed) so weather permitting, I’m desperately hoping for decent results with it over the next few days!
It might happen, and as Wayne said- “Yeah, and monkeys might fly out of my butt.”

Patience Grasshopper....
As to the image itself, yes Lee- it’s a bit overcooked, but as Greg & Colin remarked, there’s a lot of detail there, a surprising amount of Ha surrounds the Neb itself.
Oh, and the only reason the stars are round at all is the use of Startools remarkable ability to artificially repair them.