home kill guidance from FSA attached
http://www.food.gov.uk/business-industry/guidancenotes/meatregsguid/home-slaughter-livestock/livestockguidance/#.UpDeZaJFC1s It is of course written by the food standards agency who don't want this sort of thing happening, and whilst what they have written is technically correct, they have left out some bits that might be helpful.
However having said that, that's not the route I'd suggest you go.
Firstly - the fact that they pigs are not ID'd is not a problem, if they were born or moved there at under a year of age, they can quite legally be tag free, so simply don't worry about this.
Secondly - I presume you have taken over a holding no. (CPH) - you'll need it for both the pigs and goat. If not simply come back for further help. Did you also take over a herd no. for your pigs and a flock no. for your goat? again come back if not. These are quite easily obtained, and cost nothing to get.
Once you have a herd no. then register with the movement system for pigs
www.eaml2.org.uk , and buy at least three eartags with the no. on - google livestock eartags for loads of suppliers or 'supplies for smallholders ' who post on here is a good source.
With holding no., herd no. tags and registered with eaml you all ready to buy and sell livestock !
I'd recommend two courses of action.
1. Sell the pigs as "cull" stock into the market or direct to your local abattoir. If you look on our website you find the good abattoir guide
www.oaklandspigs.co.uk/abattoirs which will list ones near you (and I expect other TAS people will recommend). Phone the abattoirs and see if they want two cull sows and a cull boar. If they are interested ask them who does transport, and they should be able to tell you of a local haulier. They'll pay xx pence per pound for them, and this should easily cover the cost of transport and give you some seed money for some weaners which will better suit you. If the abattoir won't you can similarly get them hauled to a local livestock market (is there one in Camarthen still?) - again phone the market, and they'll know who hails pigs in your area. You'll get less at market, but should still make a profit.
2. Do them off for sausages. Firstly you'll get an awful lots of sausages from one pig, let alone three. Expect around 300 bags of 6 sausages weighing a pound from a reasonable size sow! But again you could send one of to the abattoir for yourself, and the other two either sell to the abattoir or the market. I'd not sausage a cull boar, sell him instead.
With the money you get, buy a couple of weaners in the spring, and invest in some fencing, and start pig keeping as a great way to get bacon, ham, sausages, leg of pork, pork chops - all tasting great !