OpenWrt for Zyxel WSM20 (Multy M1) development discussion

Hi All. Just flashed my device with the initramfs-kernel.bin, now trying to connect via ssh as per the instructions - but no joy. I can see the device on the network (listed as OpenWrt) and I can ping it when it's plugged in via the WAN ethernet port - but it is not listening on port 22! Any ideas please?