Well, whenever you find something for a much cheaper price than the norm, you have to identify the factor that makes it expensive normally, and how that factor might be mitigated to lower the price.
I know nothing about Surrey Bikes, but they're obviously expensive for a reason. What is that reason? Could an online vendor get around it and still provide a reasonable quality item?
Now, what's most concerning is that I did a quick search for Surrey bikes and found a $400 option on AliExpress, but then found a nearly identical option for nearly $2000.
What this tells me is that the price in the thousands is still the norm, even through Ali, but that one option is abnormally low, even for that site. So there's still no explaining why it's so ridiculously low.
That's most concerning, because unless you can identify an acceptable reason for a lower than normal cost, then chances are the reason is not acceptable.
Example: it's actually a mini version for toddlers, or the pieces are made of extremely flimsy material that will break and launch your children into traffic, or you'll actually receive a shower curtain with a picture of a Surrey bike on it, etc.