Question Author
Thanks for both of your answers, and you have both made me feel so much better, and I think you are gonna be right.
Since then, this evening, our older cat has had a few 'going out in a huff' sessions 3 or 4, only to creep back in again 5 mins later to sniff about and check out the kittens tray, and bedding etc.....and your right we have given lots of love and fuss to the older cat, but we have also let her see us stroking the older one a little...
Through the course of the evening she has also done an attention stunt and gone out in a huff and returned with a mouse (what a classic!!!!) and had us all chasing after it - but now she has been in the same room with us and the kitten (albeit the other end of the room) but she has done it, and hissing has reduced....she now seems facinated
Only to then fall sound asleep so she must be feeling a bit more relaxed...
THanks, I'm now sure she will be ok