Any renewal of an (expired) rating now requires a course at a flying school
before you can fly the proficiency check.
Not true.
AMC1 FCL.740(b)(1)(a)(3) provides
guidance only,
not mandatory requirements.
Not true.
To renew a rating a candidate
must present the examiner with
a Course Completion Certificate prior to LPC - therefore they
must
have done a course at an ATO/RF (even if it was zero hours long).
Exactly as Cobalt stated