Broken timing sprocket

i have been looking through past threads and can not find the information i'm looking for?
I have broken the timing gear sprocket on the diesel pump whilst fitting another pump with marked woodruff key.
we have RAVE wihic states removing the head to get the front cover off, but just want to confirm that to get to the timing gear we have to remove the head or is there any other way of doing it.

The cylinder head sits over the top of the case and the sump sits on the bottom of it. Sounds like you made a lot of work for yourself. How did you manage to break the timing sprocket? Pretty difficult to do that.

I bought a 2nd hand pump and didn't check the woodruff key, when we tightened it up we heard a crack, on removing the pump there was a fracture in the sprocket, the marked woodruff key tried to splay the sprocket where the key goes, and thats how i ended up with a broken timing chain sprocket.
I have paid 600 to have my pump recon now so going to go ahead and whip the head off, was just looking to confirm that i had to do it.
I have made alot of work for myself and gutted but i have alot of money out now may as well carryon.

I was stripping the head off my Range Rover for the wrong reasons, ie broken timing sprocket, but got a bit of a result, on stripping the head off we found a water leak between the head and the front cover which would never have been found and that i had a badly worn timing chain tensioner which was also weak, so all has been replaced and on my rebuild