Lambing ropes
Torch and spare batteries
Towels and a plastic open tub ( empty lick tubs are great ) for the used ones
I'm another for the iodine spray rather than dip, but I do make sure it dispenses a decent amount rather than a slightly wafty spray works best to get the coverage of a dip, without any potential ( and I am sure very small ) chance of cross contamination. I also can't knock it over and spill it. Although I can sit on it, and ruin a bale of hay, and my jeans, and have a backside stained yellow for 10 days.
Old style plastic housework/cleaning spray carry tray ( grooming tray if you are horsey ) to carry gloves, iodine spray, kickstart, ear tagger, ear tags ( in sealed bag ), elastic rings and applicator (ditto ) and colour spray - then you can go in and do ""stuff"" and keep everything together. The right type of carry tray also sits on many hurdles, rather like a hay rack, which is useful.
I keep calcium and twin lamb drenches, as well as the kickstart, but I don't keep antibiotics or analgesia - My sheep are in single figures, so I work on the basis that if I need something like that, I can go to the vet ( or get the vet out, whatever is needed ) and the cost is likely to be much the same, and I am not limiting myself to one type of antibiotic, or having to get in a couple, to cover various issues, and have them go out of date before getting used up. It is different when you have a few sheep, to having a farm, I'm sure, so for me that works ok.
Good luck - I am sure you will do fine, and have a fantastic experience. Keep a Mars Bar pinned to the wall, for that moment when you see the first signs of a water bag from the first girl - the nerves, panic, horror, thrill and massive surge of adrenaline, will require treatment. Also keep a book - as you will need that while you wait for the sheep to move to the next stage !