I have come across individuals that have had their flights checked and had to re-do them. This was not because they did not do them but because there was no evidence to prove it. To make sure I would try and get a form (similiar to the PPL qualifier) signed.
Nb; The CAA are wise that many a dodgy pilot may not fly it and put an entry in their book!!!(esp in another country) and if it turns out that person lied..........not nice!!