SRG 2105 "qualifying cross country"
This is a meaningless document. Its origins lie in the old National AOPA syllabus which continued to be used long after the demise of the UK PPL. The Qualifying Cross Country was a flight conducted as part of a UK PPL prior to 1999. This flight could not be undertaken until after the Navigation Skill Test had been successfully completed. In many cases it was completed after everything else including the GFT, and was thus referred to as a "Qualifier" in those days it had a validity of 9 months. Because it did not form part of the "training" it required signatures to prove it had been completed. That ceased with the introduction of JAR-FCL. It is an experience requirement that has no validity period!
FCL.210.A PPL(A) — Experience requirements and crediting
(a) Applicants for a PPL(A) shall have completed at least 45 hours of flight instruction in aeroplanes, 5 of which may have been completed in an FSTD, including at least:
(2) 10 hours of supervised solo flight time, including at least 5 hours of solo cross-country flight time with at least 1 cross-country flight of at least 270 km (150 NM), during which full stop landings at 2 aerodromes different from the aerodrome of departure shall be made.
Once you have it you have it! There is no EASA requirement for any Certificate other than the training records but the CAA seems bogged down in things it clearly does not understand.