Urenco currently just produced HEU for civilian use.
The UK has a reported stockpile of 22 tons of HEU, each PWR3 reactor contains around 200Kg of HEU which it burns at the rate of 6.06Kg per year during its working life.
Working on the basis of 4 Dreadnaught, 5 SSNA for Australia and 7 for the UK as Astute replacements will need around 3 tons over the next 30 years. So there is no rush to restart production.