The V10 is quite a common stick vac. With a large amount on the open market, there’s a higher chance you’d hear some issue here or there. Parts fail, life expectancy I’d say is anywhere from 2 - 5 years. I guess this is why they offer a 2-year warranty. 

The way I see it, three choices are in front of you.

1. Under two-years old, wait for the part to come in stock. Use their notification option or call the service team. The stock level is different between the website and their allocation.
2. Over two-years old. Order a part from somewhere else. Give the How to: Order spare parts and accessories | Dyson Community post a read. There’s a handful of authorized parts retailers.
3. Upgrade the machine to a newer model. 

I figured you’re in England/Great Britain, as I noticed you used sterling pound (£). Have you tried their ‘Part’ page: Dyson Cyclone V10 vacuum parts | Dyson. I can see some stock showing!