First-Congratulations on Derek and Clive (are you are a fan of Pete and Dudley?)
There are loads of threads on here with advice about guinea-pigs especially outdoors.
We got 2 boys (1 year old from rescue) in October- they are my DC pets but of course I do the animal husbandry . Are yours babies. Are they brothers?
I've had loads of GPs as a child (14 over the years) but these are my first adult boys.
Make sure they have enough room. Especially as they get older. They reach their 'terrible teens' about 6 months (I missed that Thank Goodness). There is a website that gives minimum sizes for GP houses. Mine have a wooden playhouse 5'5" X 5'5" with a large 3'X3' wooden box inside .There's a ramp to take them on top of the box (carpeted). Some of the cages have really steep ramps. A baby GP could climb it, an adult would struggle.
Give them some cardboard boxes to play in (you can change when they get dirty).It gives them a bit of private space if they get fed up with each other. 1 box per GP + 1 spare.
Bedding-I use rubber car mats to insulate and keep it dry. (not the carpet ones) Then newspaper, cardboard, Megazorb (horse bedding).
Hay does flatten down and it gets wet/dirty. They eat the bedding too.Mine have never fathomed walk to the hay rack.
Their box will take half an XL bag of Pets at Home hay. I've got Readi-Grass (again horse product) dried grass, They eat it, it's short pieces so not cosy like hay.
I give mine 2 hotwater bottles with fleece covers and a SnugglePad in the hay box (not the past few days though) but when it has been really cold. TBH I don't find the SnugglePad much cop. It's not as warm, and it's hard. I usually find the GPs sitting on the covered hotwater bottles when I bring them in.They are in at night, go out in the playhouse 6am.
They've got a light and a heater(one of those tubular garage heaters) with the plug in the garage.
The advice on here is no straw, no sawdust, no shavings.(Lots of GP bedding threads)
Mine have an indoor cage (about 4'x2'x 18"). We had to separate with a grid because they were scrapping. They are fine outside. (That's why you need the space with boars). I use Catsan with fleece on top. (Control the 'aroma')
Food wise- Excell pellets (orange bag) water-which they don't drink-, the hay and fresh veg am and pm.
Healthwise they are robust.You need to protect them from cold and damp.They don't like wind. They can very quickly get respiratory problems.Most of my GPs I had as a child had a 24 hour cold at the end which finished them.They mainly had good long lives.
Boars tend to be a bit more fragrent IMHO, some would disagree.One of ours 'marks'.As soon as he goes into the clean cage he plants his bum down and leaves a few drops of cloudy wee. He tours round the pighouse, purrs,stiff body, marking. Then he's fine. The other boar doesn't mark.
They can get anal inpaction (stuck poo) when they are older. Nice !