I think in todays day and age, someone who is 30 may appreciate some skin cremes? I know that my girlfriend loves the idea of Charlotte tilbery magic cream because the influencers she watches all bang on about it. You can get a set for about £50
https://www.charlottetilbury.com/uk/product/the-gift-of-magic-skin-kit?istCompanyId=3dfffc45-1529-45a3-a883-dba601d7c955&istFeedId=531587ba-0c6c-4397-a202-a1570efe3443&istItemId=iwmwxlpwx&istBid=t&gclid=CjwKCAiAqqTuBRBAEiwA7B66hQZYoiQUOHoZfBK-iJxPX5sBfeu9kriQgQovsVP8w41WdS6JYDZjkBoCIDcQAvD_BwE&gclsrc=aw.ds
Another idea is a house plant. If she is a home owner (I assume at 30 she may be) then a nice plant in a nicer pot could be an idea? Plant pots can be expensive so make sure to pick one to match her decor.
Women seem to love chocolate so maybe some from here?
You could even go a step further and get her a hot chocolate maker.
https://www.hotelchocolat.com/uk
Try to think of something she would want to buy herself (might be hard if you don't live together) but probably wouldn't, so instead would make an ideal gift.
Very good quality, comfortable and warm socks and pants would be ideal at this time of year, especially as it's so cold. Following this idea, any type of nice hooded sweatshirt or hat / glove combo is a shout.
A hot water bottle would never go a miss, along these lines you have dressing gown / slippers etc..
A personalised gift can be nice sometimes, so depending how she likes her home decor, you could get her a personalised coffee cup / hot chocolate cup.
If I was you Gherkins I would try and pick three or four different themes, and try to get 5-10 items each from that theme.
My girlfriend recently bought herself a foreo. It's a device to help with skin care routine and they come in a range of prices... Maybe something to look at?
Gift ideas are hard without knowing personal attributes of a person but a general idea is to buy something that isn't usually expensive, but to then buy a very good quality version of this, which is what will bump the price.
If she's a lady who cares for her skin, i highly recommend you get the three 15ml Charlotte tilbery samples, slightly over £50 being £55 / £53 but I think it would be appreciated.