Thank you all for the interesting reply's.
She did have antibiotics before the opp but she just got worse quick. So we got her back there sharpish before she was too weak. Fatal leaving a sick animal till it's in a sad state. No blood in the stools. No sign of anything. I even thought perhaps she'd had a migrain! Or today I was thinking toothache??
I don't think it's an acid problem as it's not all the time. But if this persists I will mention that one as that sound like it could be another avenue if things go wrong.
She's on another type of food now and we have seen a marked improvement. She is more warey of me now so almost on the mend? We bought her from Stert Cattery in Burford (UK) and she was kept in a cage most of her early days. She was brought to us in their kitchen and placed on the table. They pulled up the lid and she rose up slowly, so scared. We felt so sorry for her we handed over the money and left. I also think she was the runt of the litter as she's not as big built as out British 'red' male Tony (looks ginger to me and he's a bit of a thick'o). So we bought her thinking she was a kitten only to find out on her records when we got home she was 22 weeks! The woman was very rude on the phone when I explained there must be something wrong as she was so small compared to the documents....she wanted to give us a refund and said 'if don't love animals bring it back'. NO chance she's going back to them!! She's a nervey cat indeed. Took her years to get to the point of trusting me let alone men in general. We bought Tony from a propper breeder up near Liverpool the second time we went looking. We actually saw the mother and father!! They were HUGE!
Anyway....she's picked up a bit today! Been in the utility sink licking the taps, so getting about more.
The opp was a waist of time. The antibiotics and forced (asissted) food is working as this encouraged her to drink (salty food?).
She's having daily shots of antibiotics. She had a temperature after the opp but she's okay now.
The food we are now giving her is called Royal canin vet diet 'gastro intestinal'...feline. She has 15ml 3 times a day. 8am/1pm/5pm.
She has kept this down so far.
Sorry to hear yours is sickly too