Kondor over london

Both my uncle and my dad (keen aviation enthusiasts pre-war) lived at
Hornchurch-Romford. They both remember seeing an FW Condor over
Romford, at low level (I do not have a date) being attacked by
Spitfires out of Hornchurch. One of these was shot down by a tail gun
in the Condor.

Questions:-
did any Kondors have a tail gun? - i cant find any reference to this
What on earth was a Condor doing over SE England?

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