The mistake I made was undercharging for conservatories that were fitted after I took the house on. This was when I was trad, I knocked off the price of the patio door and the window over the con roof, and maybe there would be another small window too. I found my hourly rate was dropping on houses with conservatories.
I put the price up, but also offered to do the house only, and let them do the conservatory themselves. A few went for this. I didn't mind as it was costing me money to clean them. I am still earning less per hour when doing lots of conservatories.
Don't forget, it's no advantage having widows on the ground floor when you switch to WFP. Price conservatories as you would any other windows. Dai