>>>>> "Michael" == Michael Kay <mike@xxxxxxxxxxxx> writes:

    Michael> I would be interested to know what other XSLT 1.0 or 2.0
    Michael> processors do with this one.

Gestalt is producing:

<?xml version="1.0" encoding="UTF-8"?>
<doc nr="">
  
   <a mark="true" nr=""/>
  
   <a nr="2"/>
  
   <a nr="3"/>
  
   <a nr="4"/>
  
   <a mark="true" nr="5"/>
  
   <a nr="6"/>
  
   <a nr="7"/>
  
   <a nr="8"/>   
</doc>

-- 
Colin Adams
Preston Lancashire