Grumpy: Note that you don't have to take out the innermost two bolts - the oil pump cover bolt holes are open on the inboard end. Not the best description, but I found a picture taken yesterday. It's a bit off focus, but look closely on the inboard side of the upper cover bolt and you'll see that the bolt is visible.
So, here's how you should (try to) do it:
1. Loosen the four cover bolts
2. Remove the two outer bolts if you manage
NOTE: I did mine last year in the frame and it was tight - I had to also losen the two (top) oil pump housing bolts to get some free play, and leave the bolts in the pump cover, wriggling it off.
3. Pull cover sideways out/wriggle it out
NOTE: There is nothing in the way inside...
4. Remove oil pump shaft circlip (on the innermost gear)
5. Pull the gear off
NOTE: There is a key on the shaft that will come off/or you have to take off. At this stage, you could mark both gears to get it back the same way & aligned with the other gear. At least look closely if one edge is slightly chamfered or there is a mark on it (mine wasn't).
6. Loosen/pull out two top bolts
7. Pull the gear oil pump housing straight off.
NOTE 1: The shaft will stay with the engine as there is antoher circlip holding the drive gear - so don't push the shaft in.
NOTE 2: There is a key on the shaft also for the inside gear so when you pull off the pump you need to pay attention.
NOTE 3: Be careful when you do this so you don't gouge the soft aluminium housing & cover