First things first. The page you found via a Google search contains old, out-of-date information. Namely, it addresses the rules prior to 2014 and does not account for the rule changes that became active in April 2015. And they don't even get the old stuff from pre-2010 right! Finding old information or old attestations from discussion forums are a damning factor where UK visas are concerned. Avoid it, the net is not necessarily your friend.
In the prior regime there were categories of visitor visas called "Business Visitor", "Family Visitor", and "General Visitor". People were finding these rules unfit for purpose and the Home Office opened a private consultation with the UK legal community and this gave birth to a new set of rules. The new kind of visa is called "Standard Visitor Visa".
There were lots of changes but the biggest changes affecting you are...
- The holder of a Standard Visitor Visa (SVV) can engage in any
combination of the permitted activities list. It means business
activities, tourist activities, romantic encounter activities, family
activities and so on are all permitted in any particular visit. So
you can attend meetings and then go on a commercial tour or a self-guided tour or catch up on the new films in Leicester Square or go to a bordello or make new friends or engage in any other activity on the list (as long as you can explain how what you're doing fits into a permitted activity).
- The SVV is normally issued for a default term of 6 months. That
doesn't mean that a person should stay in the UK for 6 months because
a person's time in the UK should track the person's premise and
itinerary give or take a reasonable amount. So if you want to take extra time to tour around England, Scotland, Wales, or Northern Ireland, tell them about it at the application stage.
I wanted to travel around after the interview as well
That's wonderful, they like it because tourist revenue is a vital part of the UK economy (and Parliament relies on British missions abroad to help make this happen). Consulates are supposed to issue as many visitor visas as they can (subject to the applicant's suitability). So write it down on your application.
My question was meant to be more like are all visas given for 6
They try very hard to be uniform about it and give everyone 6 months. Issuing a lesser period is possible but they have to change the machine and run a single passport through it and then reset it again and this invites mistakes and similar operational problems. That's part of why they 'standardised' it.
Or is it possible that the visas might be given for just the duration
of travel based on air tickets?
Bzzzzzt! Wrong. They don't want to see air tickets during the application stage. Read the guidance. And stay off the net :)
Relevant Web Sites
From the "gov.uk" domain...
The Standard Visitor Visa
The Rules (which also contains the permitted activity list)