Granted, its best to worm before leaving, but im not a breeder, and so I didn't. How did we ever manage before before all these medicines, injections, and wormers?
I'm assuming from this comment then, that you don't intend to have another litter. Personally, whether your a breeder/have an accidental mating/buy a sow who is already pregnant, then you should have had the litter wormed.
I've had far too many people buy weaners who havent been wormed, and then they wonder why their pigs are coughing and not thriving, most are first time pig keepers and if we want pigs to last especially any rare breeds/bloodlines then we need to let first time pig keepers enjoy their pigs, as without them where would breeders sell their weaners too, and where would new breeders come from.
You have to think about the end product, not just till 8 weeks, or whatever age you choose to wean/let them go at.
Well worming, keep less stock, rotate your land, or leave fallow for the appropriate number of years.. most "backyard" allotment keepers dont have that option, and pig feed isnt getting cheaper.
Iron injections, well as HappyHippy said isnt a must, it really does seem to improve growth rates, i imagine if your free range and your soil isnt lacking, then your probably fine, but they are so quick and easy to do (assuming you know how to hold your piglets... I found arm under tummy, and hand around snout tucked up close against me, was the easier way and the sow was far less grumpy.. happyHippy, how do you hold them?).
Never done vaccination, but looking back I think the farm should have done one for Erp.