Being German, the extractor will have been designed to plug into a 16A German (Schuko) socket and the internal wiring will be sized accordingly. With a UK plug or adapter fitted, total current / power will be limited by the 13A plug top fuse, hence the reduction in spec. for the attached tools in the UK instructions.
On my gear, I tend to leave the original 16A Schuko plugs fitted rather than changing them and have a few adapters so that I can plug into UK 13A outlets or 16A industrial depending on what is available. Dust extractor, tracksaw and mitre saw are all like this so far.
In practice, a 13A fuse will carry 16A for a little while without blowing, so you will probably get away with it. Just keep an eye on the plug and any socket that you regularly plug it into in case repeated / heavy use cause overheating. If so, stop and sort out a proper 16A outlet and a blue CE plug to match.