Glad you have it sorted. For others that may come across this thread, the answer is "neither"
You should normally apportion costs based on the actual usage of the room, not the amount of time it is available. Usage is usually different on week days and weekends, so this calculation is usually done on hours used per week. e.g. 8 hours per day 5 days per week = 40 hours business use, 2 hours per day 5 days per week and 5 hours per day Sat/Sun = 20 hours private use so business proportion is 40 / ( 40 + 20 ) = 67%.
If you are working out your allowable expenses your your premises ( working from home)
I would be claiming for 1/7th ( based on rooms.)
I do not use this room all the time ( other family members use it also) so would allow 95% time to me and my work- OR the number of hours I work in a year.
What I am unclear about is this: if I base my figures on number of hours in a year, do I assume the room would be in use for 24 hours, or factor in hours when we wouldbe sleeping- so the room could notbe used more than say 16 hours in any day?
Would it be best to do the calculations based on 95% of 1/7th, or 95% of a number of hours that people could use the room - reasonably.