If Dyson don’t have stock, I’d visit another retailer. They have a list of recommended retailer. You’d have to pay for a replacement. 

I’d ask Dyson to place one on back order, that way you’ll get it once stock is available. 

https://community.dyson.com/ask-the-community-49/how-to-order-spare-parts-and-accessories-871

I have it on good authority that Dyson hold the sale of their spare parts on the website for newly released items. If there’s a fault or an issue that stops a new machine from working, they exchange or send a part only via the telephone. This way they are able to track and support on trends.

I’d suggest calling Dyson directly, having them either replace the part or send you a new machine.