London shopping - gifts for the kids

Moleskine, 283 Regent Street, on the left just north of Oxford Circus, has wonderful notebooks and other gifts.
On the other side of the road, Hotel Chocolat.

I'd say thank you nicely for anything from either!

For soaps/bath bombs etc, there's Lush which is a chain you will see (or, more likely, smell) all over London. There's also Neil's Yard which is nicer stuff but probably less interesting for a younger person.

Do either of them like to read? If yes there’s a great “children’s” bookshop in Richmond called the Alligator’s Mouth. Has offerings for teens.

I like Lush or Penhaligons for soaps.

Might consider a soccer shirt for your son.

Then again I encourage you to wander about Spitalfields. Suspect you can find something there for them both.

Same with shopping at any street market like Brick Lane or Camden Market.

Do either of uour kids like soccer? If so, you could get them a jersey (or other gear) for one of the football clubs.

I just took my grandson (age 15) and my granddaughter (age 11) to London and Paris and here is what they loved:

M&M store: they loved this place.
The Science Museum gift shop: Loads of stuff here for kids of all ages, and again they loved it.
Soccer stuff: We went to a West Ham football game at London Stadium, and they went crazy over all the gear and shirts in there. It's pricier so I'm not sure what your budget is, but if they play soccer, they would probably love it. Every stadium has a gift shop (Tottenham Spurs gift shop is huge) and you can also find stuff in the city.
London t-shirt: I bought them each a Paris t-shirt when we were there and they really liked those.
Tower of London gift shop: My grandson was especially enamored of this, but he loves history.
Camden Market: My granddaughter loved this place. She bought some heart-shaped pink sunglasses and had about 10 other things she was begging me to buy for her. Lots of craft stuff, clothing, bath stuff, etc.
Candy shops: Any shop that had candy stopped them in their tracks. There was one on Buckingham Palace Road (near the Buckingham Palace gift shop) called Victorian Candy Place that they wanted to stop in every time we passed it. They loved all the different British candy.

I would skip Lush as there are Lush stores all over the US. A lot of the museum gift shops have nicely wrapped bar soap.

The London Transport Museum has a great gift shop with unique items for all ages. You do not have to enter the museum to enter the shop.

London themed Phone covers are at any of the London souvenir stores, key chains, water bottles, nice bookmarks, beanies, socks? Many of the museum shops had great selections. (Especially the V & A and Westminster Abbey) Maybe a charm or necklace for your daughter?

My kids are adults, but son found the coolest tshirt at the Abbey gift shop. It was a Westminster Abbey Architecture shirt. Daughter found an inexpensive necklace she loves. Here’s a link to their shop. Lots of goodies in there!

https://shop.westminster-abbey.org/

This was the shirt he found.
https://shop.westminster-abbey.org/westminster-abbey-architecture-white-t-shirt

Near Hamleys, the Liberty of London department store the ground floor last time I was there had a lot of great gift items, beauty items and a candy department. And such a cool building worth the trip!

I would skip Lush as there are Lush stores all over the US. A lot of the museum gift shops have nicely wrapped bar soap.

I agree. St. Martin-in-the-Fields has a very nice gift shop with some wonderful smelling wrapped bar soaps, and a lot of other fun items. And they're not as pricey as some of the more high-end places.

Oh, I forgot about the V&A — my granddaughter loved the gift shop there. And the year before when I was there, I bought her a beautiful colorful stretch bracelet that she loved!

Harrods.....they have everything.

I was not aware Lush had made so many inroads in to the US- here there is also Molton Brown, which is extremely nice stuff but on the expensive side. For something a bit less expensive, the "fancy" Boots in Covent Garden (across from the tube station) has a very wide array of soap/bath bomb type items and is nicer than what you'd find in an average Boots. In general I would recommend checking out the market in and shops around Covent Garden as they have quite a lot of what I think you may be looking for.