I have already answered on the previous thread about another issue but have recommended
@AdamFrench to start a new thread for his URI in the Health/Illness section.
As far as I can see, your vet has not missed anything, as you have got a week's course of marbocyl (strong antibiotic) and you have got a gut stimulant to prevent loss of appetite, which is always a worry with a URI. You can additionally give a pinch of probiotic (available from a pet shop) to help prop up the guts and give 1/8 of a human vitamin C tablet to boost the immune system (ideally dissolved in 1 ml of water, which you can then syringe for best effect. Do so slowly and give your little one time to breath and swallow in between.
The metacam (painkiller) and the fucithalmic (eye drops) are for a potential eye infection, as your vet was obviously not able to see clearly whether the gunk in the eye was caused by an injury or the respiratory infection. Priority in that respect has to clear the eye.
I would continue with the bowls of steaming water/1-2 drops of olbas oil (if wished) to help ease the breathing.
Please contact your vet promptly if there is no improvement in 2-3 days or anytime there is a deterioration (especially lethargy). If the URI has not totally cleared up within a week, your vet may prolong the course of antibiotics. Please be patient for now and let the meds do their work in their own time.
Weigh daily at the same time (ideally before their dinner), so you can check the food intake and if necessary support her with syringe feed, to keep up her fighting strength. Start doing this when the weight loss from one day to another is over 30g or if she has lost 50g in two days.
Keep your little girls comfy and warm, but not hot.
Administering Medications