Fake ID is mostly rubbish.
I've worked on doors and the only ID I'd ever accept is passport, UK driving license (provisional included) and pass card because it's the only ID you are legally required to accept. You're not going to get a fake passport, you won't get a fake pass card or UK driving license with the holograms looking right- unless you go through proper criminal contacts rather than websites. Door staff aren't stupid, most can spot a fake ID much easier than you will be able to so if you think it looks OK, door staff will think it looks ****. I wouldn't ever accept some college card or foreign driving license.So in short, don't waste your money.
Someone else's ID is a less stupid option but odds are the date on their ID is recent. I would confiscate any ID I thought was taken from someone else and give it to the police. Your friends don't want to be going getting their passport off the police so are more likely to give you a provisional which they will have gotten recently. If it's an older picture you can sometimes get away with it but if you are claiming the picture is from 6 months ago and you don't look that much like it then no chance. If someone looked 20 and I wasn't sure their ID was their's I'd probably let them in. If they looked 18 then no chance, even if I wasn't sure enough to confiscate it I could and would refuse entry because door staff can for pretty much any reason that doesn't break the Equality Act.