Agree with HH - I have done exactly the same, I sell from the 'farm gate', it's fresh meat, boxed when half a pig is pre-ordered but the rest is sold frozen.
How many pigs you rear will depend on your circumstances but I would try and gauge interest or have orders lined up before you start or at least get firm orders while they're finishing - take a deposit too! Buying in weaners or even older stock at the beginning will probably be easier than breeding - don't forget it takes 10 months from conception to finished pig, you'd have to have pretty patient customers! But once you have a bit of a customer base you can revisit breeding your own if that's your plan?
Your 'premises' need to be signed off by Env Health, if you aren't handling the meat in any way your freezer will probably still need to be in a suitable room, your local officer will advise you on your situation and it's all free. Some have different opinions or interpretations of the rules...nothing is actually written down for us smallholders to refer to, even my EHO had to keep asking her manager in the office about my questions.
I have done the Level 2 food hygiene course, have a signed off kitchen and, after much negotiation, permission to do a certain amount of handling there (won't bore you with specifics) but things like wrapping individual joints etc. from the boxes. My abbatoir have not offered to freeze anything but it does come out super cold and freezes down quickly.
I was surprised that I have/had restrictions on who I sell to - it was only allowed to be 25% to shops or restaurants etc and the other 75% had to go direct to the final consumer, seemed odd, same stuff....I have since informed EHO that the majority of my produce will be going to a restaurant - I had to specify which one, what they were having, how it was being transported etc. I was pleasantly surprised at their common sense approach to me transporting the fresh pork, not needing a refrigerated vehicle etc, although I have got massive cool boxes for the sole purpose of moving the meat from abattoir to home/customer.
Labelling was a bit of a nightmare, you'll need specific advice from Trading Standards. I can't face going over the saga here but needless to say it is not straight forward, although I got more sense from them than Env Health!!! The easiest thing to do is sell half pigs - my abattoir puts the weight on everything so I know how much I'm selling - or get the abattoir to pack and label it all for you. Proper labelling scales cost a fortune.
The last thing I would say is on insurance, good idea to have some sort of liability insurance in place, just in case. There's nothing more you can do than advise people to store the meat correctly (this should be on the label too ) but I have always eaten some of what I sell so I know it's ok and if there was ever any comeback I can sort of prove I've done everything in my power to prevent problems.
There's a lot involved, and understandably not everyone follows the rules to the letter, if at all

but once you've navigated the minefield once it's done
