Sugar - ordinary granulated or caster, nasty bleached white stuff works better than right-on unrefined - for reducing a prolapse
Forget the strong drink, it makes you sleepy - we keep Lucozade (for him), Irn Bru (for me), Tunnocks Caramel Wafers, bananas and apples to keep the shepherd(s) going

You will be needing elastrators and rings once you start getting lambs born - unless you've decided to not dock or castrate, of course.
Twin lamb drench
Combivit or other injectable B-vits
Heat lamp / warm box / Rayburn or Aga - somewhere to warm cold lambs
Box or somewhere to constrain lambs who are recovering
Baler twine - you can make a lot of the other things you need and fix any that are broken

Some sort of electrolyte feed - Rehydion or Pfizer Scour Formula
Plenty of ready meals in the freezer, tins of soup, etc.