The bad news - four weeks is nothing in sinus-referral land sadly. Not unless it's affecting your vision... and even then.
I had a FESS in my early twenties - I am now late forties. So around late November 2025 I caught a horrible head/cold infection and it infected my heart too (I have LBBB anyway). Long story short - since then it's abundantly clear that my bone spurs have grown back (the reason for my operation in the first place) and I have had to go through so many hoops to get the secondary care referral. I have had three lots of mega antibiotics - hasn't touched it. Only thing that gives temporary relief is steroids with Sudafed Mucus stacked on top.
I have had an ECG, chest x-ray and tomorrow is a spiro test... only then will I be referred on to secondary care for what will most likely be a CT scan and/or a nasal endoscopy. And then the inevitable surgery. I have done it before, I can do it again, only last time it was so much quicker, this time it has almost taken a quarter of a year. It's the state of the chronically underfunded system that also involves people using services inappropriately. (Not saying that you are, but when people moan about the NHS in the general sphere they conveniently forget that people using it incorrectly is a massive drain).
So after tomorrow, hospital beckons and thank god and hurrah! At the point where I get the surgery notification then, depending on the duration, I will either go with the NHS or pay private because it is bloody miserable and of all the surgical procedures, FESS is very competitive.
In the meantime: sleeping sitting up (crap but lots of pillows), Sudafed (the mucus one is best for me because I am sure my head is full of gunk), extra painkillers for when the headache hits. Hot showers are a very temporary fix as they open up the airways.
I sympathise with her so much. I have had very temporary eye blindness twice in the last fortnight because of the pressure behind my left eyeball. It goes away again, but it's not fun. I am sure it won't come to that with her - it didn't with me the first time around - but definitely press for more appointments to work her way through the system to referral. I was told - because my GP is ace - that unless we do a, b and c then the hospital automatically reject the referral.
So I have done 'Crufts for Sinuses - jumping through the hoops' since then. I wish you all the best. Work hard with the NHS and once you have a consultant referral and know the outcome of that appointment then I think you make the choice about spending money on a private operation rather than a private scan earlier in the system - because often in the NHS they cannot accept a private scan, so it's wasted money.