WINDOWS ,GARDEN WALL and paving

Looking to get new double/triple glazing in . Can anybody recomend any body for the job. I would be looking at 3 windows to the front and 3 to the rear ( with addition of 3 small windows for a utility room ) , And a rear door. Based in Ballyfermot.Thinking of just white upvc.
Is the a big difference in price to get the different colours / finishes ?
Standard terrenced house.
Also what type of window would you recomend e.g. openings / u values/ triple/ double


Also looking at the following work to be carried out ideal by the same contractor.
Garden block wall built cica 60ft long including foundations and paving an area around 20 mrt2 including ground prep
If anybody could recomend anybody . Or would imprinted concrete be a better / cheaper option .
Many thanks