Perhaps it could be best to consult a doctor in that case, if it worries to you both to this extent.
Though my opinion is that it's not that big of a deal. She probably knocks herself against things without realizing it.
My mom can carry a box, and if it's too heavy, will return with a huge bruise that would last for weeks.
But considering her background, the doctor might be able to determine something. Perhaps the blood transfusion affected her blood cells and so they can heal as quickly as normal?
Not spoken to doc about it I think she has bruised easily for a while but lately one seems to go away for another one to appear
I wouldn't think that that would have anything to do with it. It probably doesn't help it, but I don't think that that would be the cause.
My mother bruises very easily as well, and most cases, she has no idea where it came from. And she gets them in the oddest places, IE: the back of her arm, her legs, her chest sometimes... etc.
I think that it could just possibly be that she simply bruises easily. Some people hit things lightly, and walk away from it without a scratch - but then a bruise arises some time later. Also because of her past medical history, she could possibly have thin blood, which might cause her to bruise more easily, since it's like her body is working over time to repair it.
I'm not sure - but it's an idea, I suppose. Have you spoken to the doctors about it?