I feel so stupid and maybe some of you are throwing their hands up now but insolved this: In the case I described above, simple port forwarding isn't enough. The The following does the trick:
iptables -t nat -A PREROUTING -p udp --dport 53 --dst 192.168.1.2 -j DNAT --to-destination 192.168.1.2:1053
iptables -t nat -A PREROUTING -p tcp --dport 53 --dst 192.168.1.2 -j DNAT --to-destination 192.168.1.2:1053
Maybe there are other solutions but this is what works fine for me.