REBASE: Ensure cached GL niceo is defined on full GL.

Author: hulpke

lib/grpffmat.gi

@@ -138,9 +138,13 @@ InstallGlobalFunction( NicomorphismFFMatGroupOnFullSpace, function( grp )
     nice:=First(FULLGLNICOCACHE,x->x[1]=V and x[2]=dim);
     if nice<>fail then return nice[3];fi;
 
+    if not (HasIsNaturalGL(grp) and IsNaturalGL(grp)) then
+      grp:=GL(dim,field); # enforce map on full GL
+    fi;
     V     := field ^ dim;
     xset := ExternalSet( grp, V );
 
+
     # STILL: reverse the base to get point sorting compatible with lexicographic
     # vector arrangement
     SetBaseOfGroup( xset, One( grp ));