For what it's worth, I can really empathise with you Gill. Tia and Jack had a few quiet days, and then went at each other hammer and tongs for ages. At 2 weeks I was ready to take him back (to Many Tears :
: ) but things got a little easier.
At 3 months after a bad fight (they were infrequent by now) the vet said
3months? well, look at your situation again after 6 months. We haven't looked back.
Tia still puts Jack in his place now and again, but quietly now.
Good luck. It depends a bit on whether your nerve holds out. You have twice the number of dogs that I had to handle, so much more difficult if they all pile in.
It is really scarey and really upsetting.