Exactly the same as my SR2, and that's where the Lister crank handle engages.  It doesn't need a shroud

This is what I found on this forum.  Hope it makes more sense to you than it did to me.

By trying to push it off by backing out those bolts will only cause the inner cone to push further into the outer pulley, thereby tightening it on the shaft.

I too have a couple of those from my dad who was a council electrician in the early 50's.  I also have his original pricker for cleaning the jet, which blocked often.  He told me they were used mainly for making leaded joints (before the days of resin joints) using a grease cloth.  2nd most important job was for boiling a kettle to make tea.  I also have a cast iron contraption that hooks onto the torch for the purpose of supporting the crucible or kettle.

Strange that Shell Rotella is not available.  Being a Dutch company!!!

I'm probably not the right person to answer your question, and I'm sure you'll get more comments, but I would say not much heritage value, sentimental value might be higher.  To me it looks like a 1970's era SR1, but I could be wrong.  As I'm sure others will tell you, please post some photo's of the serial plate.  History can usually be determined by the serial number.  Also, location will make a difference to the value.

Er, I think he was asking for everything else except the crankcase

Best of luck yourself, or is it a case of the more prepared one is, the more luck you'll have.  Sounds like you are well prepared and will be running your butte off helping out the neighbours.