The questions I had are:

• Do we use flash pasteurisation in the UK?
• How high is the residual risk for flash pasteurised milk?

Yes we do use flash pasteurisation in the UK.

https://www.dairycouncil.co.uk/who-we-are/ni-dairy/field-to-fridge/pasteurisation

Residual risk for flash pasteurised milk is high enough to be concerning, but the study didn't follow exactly the same process as industry does during pasteurisation, and those extra steps may also help to kill the virus. So we probably need another study to add in those other steps and see if the virus survives or not.

Not ideal though.

Heating the milk to 72 degrees Celsius, or 181 degrees Fahrenheit, for 15 or 20 seconds — conditions that approximated flash pasteurization — greatly reduced levels of the virus in the milk, but it didn’t inactivate it completely.

Milk samples heated for 15 or 20 seconds were still able to infect incubated chicken eggs, a test the US Food and Drug Administration has called the gold-standard for determining whether viruses remain infectious in milk.

“But, we emphasize that the conditions used in our laboratory study are not identical to the large-scale industrial treatment of raw milk,” senior study author Dr. Yoshihiro Kawaoka, a virologist who specializes in the study of flu and Ebola, said in an email.

That’s a good reason not to panic over the study findings, said Lakdawala.

Lakdawala said that commercial flash pasteurization involves a preheating step, which wasn’t done here. It also involves homogenization, a process that emulsifies the fat globules in milk so the cream won’t separate. Both of those steps would probably make it harder for the virus to survive, but she adds that the results of this study suggest full process of commercial flash pasteurization should be done “with all the steps in place.”