Slightly changed my task and it seems to be working.
Turn WiFi on
Wait 30 seconds
Wake device
Wait 3 seconds
Call 150
Wait 3 seconds
End call
Wait 3 seconds
Browse to URL and turn heating on for 90 minutes
Hopefully it will work in the morning and we'll have a nice warm house.
Controllable lights:
1 lightwave rf dimming switch in the bedroom
1 dimmable led strip in the bedroom behind the bed
1 bedside lamp on a remote socket
1 living room lamp on a remote socket
1 led strip behind the TV on a remote socket
I've got other things on remote sockets too and some spares in case I want to add more.