Where is it leaking, tho? You can expect to see some slight seepage from the diff over time, but if it's dripping on the ground where its parked, that might be a bit much.
Cast iron is  slightly porous, meaning it can/will seep liquids thru it, but not normally enough to drip. It's possible the diff has too much lube in it. If it does, then when it gets hot while driving, the lube expands, and it can spit out thru the vent, and run all the way down to the ground.
I'd suggest finding out where the leak actually is, but my feeling is, if it's enough to hit the floor, it's too much. Also, just because the seals have been replaced doesn't mean they won't leak...they might, and then they might not.

It is leaking from the yolks. And like I said it's just a couple of liitle drips after driving and then it stops.

The actual seals themselves shouldn't leak at all. You may sometimes get leakage around the outside of the seals, where they press into the housing, but a leak from the rubber area/sealing surface isn't normal, imho.
If the leak/seep is not enough to drop the lube level down, then you'll just have to clean the drips up, that's all. Just be sure to keep a check on the level, and see how it is.

the yolk might have a groove wore into it kinda like the one you get on a vibration dampner, you can  put a speedy sleeve on the yolk and replace the seal without pulling the 3rd. member, when you replace the seal put a smear of RTV around the OD of the seal before you drive it in, that way it won't leak between the housing and seal.

Could the bolts that hold on the cover need to be re-tightened/torqued.?

I  had my side yokes replaced  about a year ago and the mechanic showed me where the yokes had  actually  worn into the housing  and  he said  if I didn't  get  another  housing  it could possibly  leak  a little.  Because the seal might not seal off real good.Just wondering if your housing could be worn  a little and didn't seal off good. Just a thought.

Thank you to everyone who responded to this posting. Even though I'm not looking forward to having to do this job yet again I just can't stand leaks. You have given me some good suggestions.