My box of Singapore Crab flavoured noodles shipped from Singapore were impounded by customs for two weeks until I pointed out that the label clearly indicated there was no actual crab in them
(Crab flavour being simulated by prawn for price reasons)
So I looked into how these or similar things get to the UK shelves. It turns out that none of the supermarkets that sell these types of things, even the wholesale ones are importing them themselves, there are specialist importers who import container loads of them, do the paperwork and then sell them to the domestic wholesalers who then sell to other smaller businesses (like Chinese takeaways).
I suspect this is among the reasons that there is a very limited range of things in the UK, people only sell what there is enough demand for the importers to bring in in large quantities. And probably also explains why my crab noodles and OPs Maple syrup and not on the shelves over here.

As someone else mentioned Maple Syrup for human consumption (170220900090) is currently 0% VAT 8% Duty if imported from the USA.
Interestingly it is 0% Vat 0% Duty when imported from Canada.
Commodity code 1702209090: Other - UK Integrated Online Tariff - GOV.UK