4090 performance from the 5080 with less VRAM at around £1k would be ok, though I'd hope for a little extra power. I worry it'll be about £1200 though, with little movement on the price/performance scale.
I'm getting a nice little bonus in January so will almost certainly be getting one, though I'll be using my CC to get it initially (the one negative on my credit rating is the lack of one, I'm too careful with my money apparently!). A 5090 would be nice, but the fact the price difference between the two looks like it would be enough for a full platform upgrade means I'd rather consider the latter option to give my daughter her first PC.