On Tuesday, October 22, 2013 2:17:57 PM UTC+1, Martin Bonner wrote:
The difference
is that if the house blows up, it is not enough to say you
thought you were competent. You have to show that did everything
according to the regulations (which, given the house has blown
up, will probably be impossible).

Unless you've uploaded your pipe size calcs, benchmark certificate and manometer and flue gas analyser readings to off-site backups.

Owain