You do not say how large your area is, what is the area going to be used for if you are only patching garden centers are fine.
I have relayed 3 lawns over a 12 year period (we move alot) always gone to Turfland in Southport
www.turfland.co.uk / 01704 888333 they deliver and you can go and look at the different types of turf.
Ground preparation is key poor ground will kill your turf.