Right my two pence worth.
Im a kitchen and bathrom fitter and have been for the last 9 years (self employed).
I started tiling long before that and since then got into plumbing etc.
I started a new bathroom today, like for like straight swop with 19 mts of ceramics and also laminate floor (like you not my choice!) Also gotta tack and skim the ceiling.
I anticipate being finished by Wednesday next week. I have allowed for starting the tiling on Wednesday (providing any skim i have to add will be dry enough)
19 mts will take me 4 days with soil pipe boxing, end of bath boxing and all reveals and header of window, that tile and grout btw.
Timing is only crucial to your price if they could get someone faster as it could potentially work out cheaper for them. However if you priced it per metre then it could just be you thats out of pocket at the end of it!
Im glad from this post that Sean takes a long time on the windows and its not just me! I go home sometimes and look and think i have only done a few metres!
I think this post just goes to show the speed difference between us all and by the time this thread is finished should show some good results.
Good luck with it