Car wont start??

[Hector-8]

Car is a Mk2 Golf GTI 16v
Alarm Toad 101cl

On Friday night I heard a chirping/ticking coming from the car. I couldnt open the doors as the battery had run flat. Manually opened and lifted bonnet. I traced the noise to the siren box of the Toad alarm. A constant tick/chirp 2 or 3 a second. So got the jump leads out and wired it up to the hyundai and she started straight away.

Left her running for about 30 mins and then put the battery on charge.

So the following morning I wanted to wash the Golf but she wouldnt start, all electrics, windows, etc are working. I have a votex console and battery is reading 12+. I also tried jump leads again and nothing, swap batteries from hyundai to golf and vice versa and hyundai starts with both batteries and golf with neither!!!

So Im thinking its either alarm related or starter motor (surely not starter motor as it started night before??)

this is where i am stumped and need advice. thanks

[Seanl]

Think you've answered your own question tbh mate. I'd disconnect your alarm/immobiliser as its obvious its having issues. If your not confident yourself, get a mobile auto sparkie to do it, he may come across the fault if it obvious as well. 

[KRdubber]

Hi, have you got a small battery in your alarm/immobiliser?