Why have HR asked me this and can I say no?

[Hrrrrhr]

I started some medication recently. A side effect is drowsiness and on those occasions not driving. It’s supposed to settle over 8 weeks. I’ve therefore asked my employer whether I can work from home during this time. My job can completely be done from home and often is. I’ve been there a long time. They’re asking me if they can contact my gp and ask my gp a number of questions instead of going through occupational health as occupational health can take much longer (ie beyond the time I’m asking for to have the adjustment anyway). I’m not comfortable having direct questions sent to my gp as I’ve never heard of this before. I would prefer occupational health. Can anyone explain my rights? Thank you

OP has already said she frequently works from home.

I don't see the problem. If the job can be done from home it doesn't matter where it's being done, as long as it's being done. If there are meetings they can be done via chat/zoom/phone.

You need better OH🤣 the provider we use for most of our clients turns it around in 24 hours. Much quicker than a GP referral. And much more useful in practice.
As for the costs - some on the posters on this thread need to look around. Ours is barely more expensive than a basic GP report...