I've been sorting out fridge problems with help from the list for the last 2
weeks. What has helped me particularly has been the advice to seal everything
with silicone that might cause air leaks and to check the actual pressure
output of my regulator.
If you opened the combustion box at the back for cleaning/blowing out there
might be an air leak. If you're going to be at high altitudes in SA you might
want to verify your regulator output so you can decrease the pressure output
to keep the flame going. Since the problem occurred when you cleaned it I
suspect the former, but while you're at it you might want to replace the
regulator if it's the original square type. They can fail. FWIW I checked
around here for new regulators and could only find a sealed, non adjustable
type so far.
Good luck,

Ken Hunter
82 Westy 1.9D
84 Jetta 1.5D
89 Mitsubishi van