Thinking about it, it’s really, really odd that there’s such a dearth of good quality, non-generic / not insultingly stereotypical things that a choosy, middle aged person might want as a gift, costing no more than £20.
It’s incredibly easy to list all the things one wouldn’t want as a gift - harder to think of things that would be welcome.
Most Folio Society books are more than £20 now, unless you stock up during the sales.
I adore the look of Persephone Books, and many of their titles are fabulous (Marghanita Laski’s ‘Little Boy Lost’ is one of the books of my life) but it worries me that they’re seen as the go to genteel present for apparently genteel middle aged ladies.
I like a particular type of wine and am unlikely to drink any outside that category. And decent spirits - always welcome - cost a lot more than that. Not forgetting that some people don’t drink. And don’t want to be inundated with chocolate.
There is almost certainly nothing in Boots that I want someone else to buy me. I buy most grooming / beauty products online - and even if Boots has cosmetics I use, I prefer to choose them myself.
Are there any magazine subscriptions within budget? Would have to be very obscure, otherwise I’d already have a subscription if I wanted one.
‘Nice’ soap from TK Maxx or a fancy perfume shop? Bit uninspired - unless Santa Maria Novella, and you wouldn’t get much there within budget. Candles, ditto.
Space NK used to have a good selection of neutral balms and unctions (haven’t stepped into any of their shops for years) but again - price!
Sports equipment? Difficult unless you know the person well.
Travel accessories? Generic, and nasty if cheap.
I really like a particular brand of linen tea towel - but you’d have to know where to order them from.
Bed linen impossible. One tiny towel pointless. I’m middle aged; I’m on top of household stuff and do not want random clutter.
As a pp said above, no clothes or accessories suitable as a gift would be within this price range. I often include something like a basic cotton t shirt in a Christmas stocking for family members - but from a 75 (?) year old woman to a 56 year old woman that would be a bit odd.
Garden stuff I prefer to choose myself.
I get coffee beans on subscription.
Very good, loose leaf, maybe single origin tea - this would actually be fine! One ‘posh’ teabag in a mug, 
… Okay from a child.
Extra virgin olive oil - fine.
Honey - fine.
I hate ready ground spices, no matter how expensive.
Beyond that, I can’t think of much that doesn’t get flung into the Ocado trolley.
Cheese! Order a decent wedge of prizewinning cheese. That would do. 