I got it sorted in the end.

For some reason the AP800 acquired the IP address 192.168.1.11 even after ‘hardware resetting it’…. that is never going to work on my home network as that address happens to be a DNS server!
It also meant, the firmware upgrade didn’t work because I was expecting either the IP address is was (192.168.1.252) or the default (192.168.1.2) that it was out of the box - and the manual says it should be post hardware reset!

In the end I connected to it via WIFI using the default config (i.e. post hardware reset) from a laptop connected to nothing else and did a port scan to discover it was on 192.168.1.11!

Most annoying, but solved in the end

Hi for all users ... new firmware is out today
ftp://ftp.draytek.com/VigorAP%20800/Firmware/v1.1.2/

babis3g wrote: Hi for all users ... new firmware is out today
ftp://ftp.draytek.com/VigorAP%20800/Firmware/v1.1.2/

And just a word of warning for others, I applied this my AP800 came back up with a DHCP assigned address instead of it's fixed address, which took me a while to realise. Bit annoying.