I have a Bosch steam generator iron, which has just started emitting
dirty coloured liquid. I live in Scotland so descaling should not be
an issue. Can I assume it is faulty as I have not put anything in
other than water and the brown must have come from somewhere?

I have checked it was not picked up from other clothes. The unit is
quite old now. I don't want to risk collateral damage.

Is there a better option than Bosch?