I sell complete motor wheels for about £150. Is it worth getting them from abroad?
Many factors. Firstly, they have a 210 rpm 36v one, which is perfect for 48V. After that, it's a question of whether you can get the right speed motor in the right wheel size, then you take the price, add on the shipping and apply the discount code, then compare what you get for the price with alternatives. They say that most accessories are shipped from UK warehouse, so no extra VAT or duty.
That's probably what most people would do, but there are other important factors, like quality and support, which we're not yet in a position to evaluate, or you decide whether you have any old friends that supply this stuff, and whether you owe them any favours, or you decide to support your favourite supplier because they're struggling and you don't want them to go out of business.
When I buy stuff, it's often for other people with their money, so the decision tends to be down to just the things in the first paragraph, unfortunately.