Received a new Vigor 2927 from our ISP. The router login was at 192.168.0.1   

We have a 192.168.0.0 / 255.255.248.0 subnet. We also use our own DHCP server.

I changed the LAN1 settings - ip 192.168.0.1   /   subnet mask 255.255.248.0/21    /    disabled the router DHCP server

Confirming that you get a message that it will change the other LANs because they overlap (I think). Then restart.

I'd usually then set a laptop with a static ip e.g. 192.168.0.10 and then carry on configuring it .. but I can no longer get to the login page either on http://192.168.0.1 or https://192.168.0.1

Any suggestions before I reset the router? Thanks.