Update: By golly I think we might have cracked it! At least for now anyway.
It's been a slow process with support but this morning I had the following set of instructions to try:
Please perform the following steps and update us with results:
1) Remove from Backups the Backup Copy Job chain.
2) Rescan the Scale-Out Repository after that.
3) You will be able to find the Backup Copy chain into the Disk (Imported) section.
4) After that please try to go to the properties of the Backup Copy chain itself.
5) If it is possible to browse, please map the Backup Copy chain into the Backup Copy Job and update with results about the merge operation.
6) Also try to rebuild the Scale-Out Repository and let me know is it possible for you or not.
I wasn't sure how best to carry out step 6 (I did reply a while ago but heard nothing yet) so I went ahead & completed 1 - 5 with no change, i.e. complaints about unable to find scale-out repository.
So, with nothing much to lose, I thought I'd try removing the copy job data selection from the remote site tape job (I guess that'll cause me to have to run a complete synthetic job again or will it still recognise that I have the data on tape already?) and retry steps 1 -5.
I'm pleased to say that it's currently in the process of creating a synthetic full!!!
So, at this point, properly-working backup copies are more important to me than remote tape copies so I guess I'll live without them for now in anticipation of the fix in the next release!
Thanks for the heads up, something last week made me think it was going to be more awkward removing the tape dependency side of things but I can't remember what that was now & just did it! :-/
(I might actually consider migrating the scale-out repository back to the original 2 simple repositories, is there an easy/safe way for such a migration?)