Talk

Anyone?

Never put them in a position where they feel they're competing - ie feed them separately and don't leave toys/chews/any other "prized" item lying around. Bear in mind that YOU count as a prized item - which is probably why they kicked off in the first incident you mentioned.

They both sound a little bit "guardy", so just be careful, keep an eye on them and at any hint of trouble, separate them. Better safe than sorry, especially with oldies. Bitch fights unfortunately can often be more intense than between males, and bitches seem to hold grudges more than males do. Keep a very close eye on them.

Probably more of what CK has said. If you can, it might help to keep them apart as much as you can. We have a muzzle for one of ours, who when tormented enough, chomps holes in our other ageing boy. The muzzle is more of an ornament, but at least it's there.
I've just read that they're both bitches. I would def. keep them apart as they can be sooo grudgy.

Thanks for your replies

It's true, they do seem 'grudgy', these incidents happened a while ago and yet they are a bit wary around each other. They're fine when they're out walking and even seem protective of each other around other dogs.

Today I have locked one dog out of the kitchen while I fed the other, and then shooed the fed dog outside. I just hope I'm not committing a canine faux pas in feeding whichever dog is there first!