Good job getting it out of there to gain access. One thing to try and do before it goes back in, is to check for wear for the lift lever where it pivots on the chain case. You have access, if it's worn, fix it now."You should'tn need to split the pump to gain access, would it be easier to just pull the pump out?" Exactly what I did today. Getting to the rear bolts was a real stretch for my short arms. Looks like I've got great access to the gear box mounting bolts but the chains will have to come off. So what's the level of difficulty pulling those back together and putting in a master link? Of course the manual calls for special tools.
As for the master link, it's not great, as you will be fighting the weight of the chain to get the link in, but it can be done. I wonder how you would go with using bailing wire between the two end rollers of the chain and pulling it in that way till you can fit the master link in. I have been lucky enough to have my chain case out when i did mine, i was able to stand it on the end and gravity would just let it hang so it was fairly easy.