Problem With Bolero SD Card

I have psoted this in the IC section, but am posting here in the hope of a wider response.

I have a 16gb card loaded with about 65 folders and a total of about 3500 mp3 files in the folders. None of the 'root' folders have more than 1 level of sub folder below them

The Bolero display only shows about 60% of the folders even though when I check the card on my PC all the folders and files are present.

I have tried deleting some of the displayed folders and the Bolero then displays more of the list (ie it shows a few folders which were not displayed before deletions, if that makes sense).

This would seem to support the theory that there is a limit to the maximum number of folders/files the Bolero will read on a card. However, I would like to confirm this or be able to 'argue' with the main dealer if there is a warranty fault.

As before, any information gratefully received

Malc