I have researched more and this issue is widespread, and each seems to get specific solutions so I have re-grouped and looked at this issue from a different angle.
There are several EQDir adapter solutions and not all use a prolific chip, which is at the root of this issue. I am very tempted to invest in a new EQDir with the better, and identifiable, FDTI chipset. I have not seen any posts about this adapter type, but as it is broadly USB-RS232 it should perform with Indi in exactly the same way. The costs are worth it if it eliminates this constant 'tinkering' during each setup, and the loss of Dark Sky's while doing so.
I will post results if this sorts the problem. Comments or views on this very welcome.