Assuming deadweight somewhere around 60-80 kegs per pig then yes you should just about make sense of it. And if you’ve fed them right and they’re not too fat, the meat will be better quality than you would have ever been able to buy from a shop or butcher for that money.
But, if you didn’t love keeping pigs so much that there’s a reward in that in itself, you will probably find you can buy half a pig for £150-ish from another small producer another time, and lots of those will be good quality product.
An under-counter upright freezer won’t hold even one of the pigs, not volume-wise nor actually fitting it all in - the spaces are too constrained in an upright with drawers. Some of the joints could take up nearly a whole drawer and you’d only get a few packs of sausages around it. Get yourself a chest freezer, something around 200L or more. More volume and a much more flexible space.