From the De Vere Group

https://www.devere-group.com/news/Rolls-Royce-EU-relocation-Brexit.aspx

From Derbshire Live

https://www.derbytelegraph.co.uk/news/business/rolls-royce-confirms-transfer-work-2319550

From Capital FM

https://www.capitalfm.com/eastmids/radio/news/local/rolls-royce-confirms-its-moving-some-work/

And nobody is claiming that the European Aviation Safety Authority is the only body internationally to set standards, the point is that unless/until we negotiate access/membership we have a problem.

@ Nigel;

"Do you honestly think that American businesses (or any other major manufacturing nation) have to get their engines approved in the EU?"

No mate. Did you honestly think that I did? Unfortunately, we cannot 'take back control' over aircraft engine design. We're governed by rules which we have to take.

https://www.skybrary.aero/index.php/Certification_of_Aircraft,_Design_and_Production

You knew all that when you made your post, of course.