Welcome, sounds like you are going along a similar path to me that took on 3.5 acres at the end of last year. I am also Cambridgeshire, Ramsey area. Whereabouts are you?
I had 2 Saddlebacks at the beginning of the year and currently have 2 GOS. I am now completely hooked on eating my own pork. Everyone I spoke to said start by rearing weaners as it is a lot cheaper than keeping a sow in feed and there is a lot of paperwork needed with breeding etc. I have to admit, it is much easier to buy weaners, there are loads of pig farmers in our area and an easy way to start. If you are nearish, happy to pass on contact details of the 2 places we got ours from.
I also buy from Highgate, although have just discovered feedability in pondersbridge which is a bit closer and a bit cheaper.