Mitch wrote:

Is there a bath sealant system that exists that actually lasts more than
about a year?

Use Evostick Nail and Seal. It's a modified silicone co-polymer that has
better adhesion and superior mechanical properties to silicone. It's
easy to clean and resists abarasives and can be sanded if necessary
(*not* recommended when used on a bath).

http://www.sweetcounter.co.uk/products/ppnailseal.htm

You can get it from B&Q but not all stores stock it.

http://www.diy.com/diy/jsp/bq/nav/na...h_search=nail+
and+seal

http://preview.tinyurl.com/2gvhre

It cleans off easily with white spirit and makes a good sealant despite
the promotion being mostly as a glue.

The only negative with it is that it's available in one colour only,
white.