Is there another Hyundai dealership you could take it or is you car in dcks at your current dealer?
When speaking to the service manager again, its not too late to throw in a remark ” I take it you don’t sell cars in the likes Norway or Canada, if they aren’t capable of driving in the snow, due to such a poor design” You can also use something along these lines, if you have to make a complaint to Hyundai UK.
If all else fails, you can look up breaker’s of nearly new cars and see if they have the part and either fit it yourself or get a local backstreet garage do it.