+1 for doing it yourself.
Its easy peasy when you get into the swing of things, the hard bit imo is putting the beading on after. Just remember to let it sit in the room your fitting it for 48 hours before fitting it.
Doing it yourself will save you an absolute fortune and if it is the click fit (no glue) stuff you could take it back up (if you are careful) if you mess it up too badly and get someone in to fit it.
The floor area is not square and some awkward cuts are required. I am going to query the quote today. They want £1900 to fit a 25m^2 room and £1130 to do a £13m^2 bedroom. It seems disproportionate to me.