I don't know if any of you remember, but I had a thread over Christmas about my poor kitten who had urinary issues and had to be put to sleep.
We thought long and hard about getting another kitten - his sister was fairly settled and we were worried about introductions etc, but in the end the cat-shaped hole in our lives was too big and we rescued a 3 and a half month old kitten a month ago.
After initial growling and hissing, both she and sister cat are getting much better with each other, and we caught them both grooming the other yesterday :). The 7 month-old playfulness is back and the kitten is helping to fill the big hole that boy cat left behind (although I am still missing having a cuddle cat - neither of the girls are even vaguely interested whereas boy cat was a real lap cat).