1. When you take an image does the Indi viewer show the image as black even when stretched ?
No, the viewer in Indi shows the correct image, as does the Ekos dashboard ("Settings" tab)

2. Double check your frame settings and pixel sizes in Indi settings - I suspect this is the problem
Do you mean these settings?

3. Check your DSS is up todate
It is the current 4.2.3 64bit. I upgraded a few days ago while investigating this issue.

4. If the Indi viewer is showing a non black image then your settings in DSS are wrong
see 1.

5. In your Indi settings what are your Format etc settings set to - screen print always help here :-)
Do you mean the settings above? If not, which settings do you mean exactly? (I'm quite new to Ekos)

>> Plus take note of the colour indicators in Indi Settings - they should be all green - are any RED indicating a problem.
All are green or white

6. Load one of he many FITS viewer's for Windows and see if the image
Yes, I have a FITS viewer and that shows data in the images.

>> DSS is quite able,as you no doubt already know , to handle FITS from Indi - I use it via Astrotoaster all the time and there is no problems - so long as your settings in Indi AND DSS are correct.
Yes, I thought so. This can't be a general problem or my search before posting would have come up with either a solution, or a long list of people reporting issues. ;-) I'm sure this is something on my side (either Ekos or DSS) but I'm not experienced enough to investigate further on my own.
These are the FITS settings in my DSS: