The loud noise is the fan and this can be cured by wedging in a suitable piece of metal between the fan housing and it's adaptor plate. The kettling is fairly normal and will go if you turn down the temperature setting. This can be reduced by flushing with a cleaner. The hot water shuttoff problem is down to either: 1, the HW flow switch (common for these to fail intermittent on the Baxi Bahama) or you have the old SIT board where a hard turn off seems to lock in a solenoid and it needs a reset. the old board has been updated twice since the model was introduced.
Tony
January 2011