There’s a couple of good websites based in the UK, like propdog.co.uk and magicshop.co.uk
If you are looking for brick and mortar shops, it’ll really depend where in the country you are...
London has Davenports
Portsmouth area has the Merchant of Magic
Edinburgh has Cascade Juggling
There’s quite a few others
If there’s a Costco near you as well you can pick up a brick of Bicycles for about £20 as well