My female delivered 9 puppies Friday  normal that had to have a caeserian for the last 2, today (sunday) i have noticed she is loosing what looks like very dark thick blood (a little string hanging from her) she seeems fine in herself feeding puppies great etc, anyone come across this before?

I would say it's normal, because bitches normally lose a bloody discharge for several weeks after whelping. If it's dark in colour then it's not fresh bleeding, which would be a bad sign. If you are in any doubt, of course consult your vet.

My bitch was the same when she had her section back in the summer, like Jeangenie said it's pretty normal, but if it's to much then take her back for a check up.