Immobiliser / Alarm problem

Went to start the car this morning and found the doors unlocked, no red flashing LED on the dash and no response from pressing the button on the keyfob (main or spare, both with batteries less than 6 months old) - alarm won't arm/disarm and I can't deactivate the immobiliser and start the car. The usual 'turn ignition to on position and press button on fob' does nothing.

I have the code for the keypad, I've used it in the past to reprogram the fobs, but the keypad doesn't seem to respond anymore - there is an LED on that which I think is supposed to flash when you press one of the number keys, but it doesn't.

Car battery seems fine, I can trigger the alarm siren by pulling the cabin fuse and reinserting it (which I guess is the voltage drop detection?) and all other fuses are intact.

I'm completely stumped now... help!!

it's a 2001 bugeye with the standard Sigma alarm

id try new battery in fob/s if you have more than one..i bought batts from halfrauds when had mine tried 6 and they were all tosh..the tried a Panasonic and car fired up..
same symptoms as yours getting

yeah I thought it might be the batteries in the fobs, but the keypad override would still work in that situation wouldn't it?

mine never worked lol

yeah I've never actually tried turning it on/off with the keypad til now so who knows! Batteries are cheap enough to try and rule out first I guess