No, they just sell tyres, usually mail order. If you buy 4 tyres from them, a courier will turn up at your house, a few days later, and give you 4 tyres. What you do with them after that, is up to you! A decade or so ago, Camskill used to fit and balance, but they just retail now. I'm lucky in that I live close enough to go and pick the tyres up, but even that is getting harder, as they're set up as a "sausage factory". They cut their costs by having a pretty inflexible sales and distribution process. Anything that requires any part of the sausage factory to do anything even slightly different, causes problems for them.
I think most online tyre vendors are similar. The biggest ones like Blackcircles, often have a slider bar on the screen so you can set it to "tyres only" or "fully fitted". If you select the former, they're like Camskill - tyres delivered to your door. If you set it to "fully fitted", they have a network of tyre fitting places up and down the country. You pick one near you, and they post the tyres there. You then turn up and get them fitted. However, I've never found the online vendors' fully fitted prices to be that much better than what I can just find locally, with a few minutes on the phone.
The plus side of all these online tyre vendors, is that small tyre fitting places who would never have had the buying power to get good discounts on tyres, and don't have the throughput to be able to hold a lot of stock anyway, are now very used to people wanting "fit-balance-disposal" only. I don't think many of them would turn a hair if you just phone them up and say "I've got some online tyres, how much to fit and balance, please"?
