TBH I am just as bad as deciding for myself.
However....
Getting jewellery out there...a ring, a bracelet, a watch, necklace or earrings. Either an "everyday" piece or something special.
What hobbies do you have (or want to have)...£200-£500 is a good chunk to put towards a "big" purchase, like a cricut if you're into papercraft and related hobbies.
Kitchen Aid for baking, or cake decorating equipment.
Some sort of upgrade for sports equipment?
Its more of a house present....but a sound bar?
Tech - like a smart watch, tablet or laptop?
A piece of furniture, like a dressing table?
Shopping trip for clothes or a voucher for a particular shop with a stylist session? Similarly, hair or makeup session? Obviously I can't see you and you may be a stunning, stylist individual already.
I know you said short breaks are out...but other experiences - like a masterclass, theatre trip, or a particular restaurant?