Managed to get the bonnet open on the £0 Astra!
There is a metal rod that sits behind the main bonnet spring, this rod when pushed to the passenger side of the car disconnects the spring and pops the bonnet open. I managed to utilise an old barbeque skewer and bent a hook on the end to grab the metal rod. One sharp pull and the bonnet was open. The reason why the cable had failed was that the clamp that holds the cable taut had completely broken and was missing so the cable was flapping looser than Katie Hopkins' mouth. One job to do before the bonnet gets closed.
I then sacked off the kippered battery and fitted a £20 secondhand 085 jobbie that I bought earlier this morning, along with a replacement grille that I smashed to pieces in getting to the lock. New battery installed and all electrical systems came back to life. Even the radio still worked. Interestingly all the station presets from when it was a hire car in Liverpool were still present, one I think was Radio City?
I thought fuck it, and turned the key to see what would happen. After three years of sitting idle it fired up first try and idled perfectly, along with a cloud of blue / grey smoke! Turbo has definitely shit itself! I drove it up and down the (private) cul-de-sac and all seems okay. Even the brakes came back to life a little too!
ALL VORXORLS RNT SHIT.