NavList:

"almost-landlocked Germany"  Better not tell the Germans.  Have you looked at your atlas recently.  it's about 130 miles from Borkum to Sylt, and about 260 miles from Flensburg to Poland.  They built the Kiel Canal to move their Naval Fleets swiftly from the Baltic to the Noth Sea and vice versa.  The West Coast Rivers contain some of the Worlds greatest ports.
"NV produces top quality charts, thank goodness...but it seems odd that you get better BVI charts from almost-landlocked Germany than you do from the British themselves."  NV Chart folios are very good, I used them in the Baltic, but have you wondered where they get their original soundings from.  Did they send a survey team to the BVI to re-survey the waters, or did they obtain their information for an existing source, posibly the UK Hyrographic Office?
"the last survey date is "more than 100 years ago"  This is not uncommon on many charts.  In this accountancy led World, the trend is to mainly survey the places where the commercial vessels are most likely to sail.  The Lower Humber is surveyed annually with the dredged chanels surveyed more frequently.  The Upper Humber is surveyed bi-monthly or more frequently as required.  At least British Admiralty charts inculde a panel showing the dates of the last full survey.  Not all other charts do.
Where was I?  ...oh yes, the British and their charts.  They are simply not players in cartography, even when it comes to their own territorial posessions.  Presumably in home waters (other than the Scilly Isles!) they try to keep up to date, but not in this hemisphere.  Once the British mechantile and Naval fleets were the largest in the World and labour was cheap.  If the UK Hydrodrographic Office has a millstone around its neck, it's its legacy of World Wide Crart Coverage to support, when there's much less UK commercial demmand.  Go to the NV and UKHO websites and look at the relative coverage. You can see why the UKHO has a job on its hands.  Companies like NV can concentrate upon producing for the markets and places where the demmand is greatest.
"The Canadians keep their charts up to date, like the Americans, on a month by month basis through a publication called "Notices to Mariners." So does the UKHO: they also sent official agents traces of the corections to make life easy.  Corections are now availabe on the WWW.
It's also inportant to realise that much original World hydrographic soundings and even chart production is shared between the various maritime nations. 
Dave