My new bathroom starts very soon. We started shopping around in January, and it's taken till now to decide what we want, find the right people and get to the point where they can fit us in.
The system was that we rang a few companies, someone came out and worked out the options, which they sent us for consideration, we discussed and let them know our preference, and they got back with quotes. They didn't quote at the start, as it is too expensive to do several diagrams and keep changing them in line with queries - I found this odd at first, but I understand it now.
We decided on a layout and chose the items, tiles, flooring etc, as well as which company to go with. They are doing everything - knocking through from the separate loo, installation and plumbing, tiling, new ceiling, flooring and electrics.
You can choose items yourself and find a company to fit, which might work out a bit cheaper, but if anything goes wrong it will be up to you to sort it out with the suppliers. A full-service company will do everything and deal with anything that crops up.
Ours will take a couple of weeks, but as I say, this involves a little bit of building work, and also moving the loo, which is a bit more complicated than usual.