I have sorta dug myself a hole. I mentioned £60 but i told her that is without the inside roof.
I said that i would work out how i will do the roof and get back to her with a price today.
The access to the roof is not great on one of the shorter sided of the conservatory as there is only about 2m between the cons and a fence. And im not the tallest guy in the word.
Would you stand on a small step ladder?
Id be about £200 depending on how dirty it is. I would charge per hour and give an estimated price.
I use a conservatory roof access ladder or a normal ladder with a stand off tied using suction cups on the glass to prevent sideways slip on the out side, and a trestle set up for inside. (inside work is long duration because you will need to move furniture about all the time and cover it up with dust sheets to prevent dirty drips)
Id also find out if they are smokers!!! If they are id test it first, to see how hard the inside will be. Sometimes i dont touch smokers.. the yellow nicotine ruins scrims/cloths and its a ball ache to remove.
Step ladders are not safe for long duration work and should not be used for sideways work due to instability.
If you have said £60 for the outside, then id at least double it to £120 for inside and out or add an extra 25-50% to make the overall price up. Least that way you can do the outside for £60 and keep to your original quote but also make the money up a bit should everything be required.