That's great, Tish - you will love your own homegrown lamb

However... electric fencing with horned sheep with their testicles on... not sure
I would.
For your first foray into sheep I think I would stick to wethers.
Not only must you keep entire males from tupping their sisters, but also from fighting, escaping and upsetting your neighbours when they tup his/her ewes... not to mention what happens if there is a disease outbreak and we all get put on standstill. (It can happen, happened our first year on the moorland farm. No live movements except direct to slaughter - a lot of people got stuck with increasingly hormonal tup lambs...)
Sorry to pee on your fireworks, but in my view it would be better to be a little more patient and wait for the right sheep to come along, than dive in too hastily and find yourself with problems.
Once you do get some, they shouldn't need much if anything besides grass and flystrike prevention, depending on where they came from. Keep an eye out for runny bums, worm if indicated. Especially be vigilant for dark dry dirty bums early in the spring, it could mean coccidiosis, which is a swift and virulent killer. If we get another cool wet summer, ask locally if you should fluke them. If they seem listless at any time, consider a mineral drench. But if they've had a good start and your grass is good, they should just grow.

Some will advise vaccination - you could give them Ovivac-P or Heptavac-P if you wanted.
Flystrike prevention from whenever the fly season starts - probably fairly early where you are.
They will need to learn about the electric - is there another fence beyond it, because wee lambs can often get through without really feeling much, something about their little pinpointy feet...
If it's the elecrified netting, then you'll need to avoid horned sheep entirely. If it's wires, personally I would still avoid horned sheep but others may have different experience to share.
Just seen the other posts - I had assumed you to mean you were buying 2013-born lambs? If you are looking at 2012-born, then you want a primitive/native/hill sheep that takes two year to mature, such as Shetland, Swaledale. A 2012-born commercial type such as a Texel should, as foobar says, have been away fat before now. And as Anke says, you'll need to clip their fleece off if this is their second summer.