"I'm sorry, but I don't know what H fare and V fare means... is that a level of fare cost? "

It is the booking class where the ticket is booked into. It is still an economy seat and the fare basis has no relevance to where you get to sit in the plane.

The airline allocates seats to each allocation and you will find that the cheapest ones fill up quicker. H is one of the highest classes ( comes next after Y and B ) and is one of the easiest classes in which to find availability. M comes slightly after H so has less availability. The One World Explorer fares are booked in L which is quite a low class. When I last travelled from UK - Oz in summer, the only fare classes available were Y,B,H and K with all the others unavailable. Given that H is normally one of the last classes to close out, it is a great class to have a ticket booked in. V and N are among the cheapest of the classes and the the 1st ones to go

Dave