Bateman
It's a simple fix. Brendan saved the day again
If you have a Skywatcher (Synta/Orion) Black Diamon OTA - try this.
1. grab the 1.25" adapter;
2. unscrew the top part of the adapter (put it aside);
3. screw your camera T-ring directly onto the bottom part of the 1.25" adapter; and
4. enjoy the extra in-focus with your DSLR!
Hope this helps.