Spotti def implantation until proven otherwise timing is just right for that.
I think normal gestation for a cat is about 65ish days. So not long. Fx she waits until after half term and the dc are back to school. It will be much quieter for her.
I swear kittens are a brilliant distraction from ttc myself. Fortunately I've had 2 home births so I've given my cat the low down on home birthing, lol. She was listening intently. 
We think its only 2 kittens. Which does seem like a very small litter, but vets will double check in couple of weeks. So have given my sister first refusal as her 14 yr old cat died a few weeks ago. Her hb is being a bit of a spoil sport though. If not some very good friends of mine both messaged me separately trying to surprise the other one. They want one. But the dc I know will want us to keep one. I'm not sure I could give them all away
but both homes are lovely.
Clearly the "oh dear how could you let that happen" question? Wasn't answered with, well I was trying very hard to get myself upduffed and er.....