Claire, I agree with the others that a return trip to the vet is a good idea. IF the ovaries have been left, there could be something wrong; on the other hand she may not be spayed at all!
Ela, Polly no longer cavorts with the local toms. She spends all her time sleeping. But a few years ago she positively encouraged any unneutered tom to mate with her. She was just a trollop! The local area is now saturated with student housing, and there are fewer cats and entire toms around.
Yes, I did consider the posibility of FLV etc, but considering that she had spent six years of her life as a feral, doing nothing BUT mating, kittening and hunting, I figure the chances of both my cats (Samantha was semi-feral, abandoned when pregnant) having come into contact with the virus at some point, is very high. They are either immune, having thrown it off; or persistently viraemic. You may remember from our discussions on CC that I hold very different opinions from you upon this issue. Neither cats have been tested, nor will be. I won't have them pts when the inevitable positive antibody/virus tests come through.
I think that Claire's friend's cat needs to be thoroughly examined, perhaps by a different vet.
But it isn't impossible that she is healthy and completely spayed.