How can i fix my vauxhall frontera?

How can i fix my vauxhall frontera 2.3 turbo diesal L reg, it appears that my timing chain has snaped. I have started to strip the engine down so that i can replace the chain, but i have only got so far. i am trying to get to the bottom cog that the timing chain goes around, i have taken the fan off, the water pump and the bottom pully. I have taken as many bolts out as i can see in hope that i can get the ally casing of the front of the engine but i cant get it off. Can onyone help im in need of some guidance. Many thanks Danny