tosh if this rooms sole use is the office then yes i think
I also use it for escaping the Missis; it's my 'bolt hole' (I'm not lucky enough to have a shed down the bottom of the garden); I also read non-window cleaning related books in there too.
In the office; while I'm sat reading; I sometimes I let my dog sit on my lap and we have a quiet moment together.
Should I deduct 20% from the total of office decoration because of my private use of the office; I'd hate to think that I was fiddling the tax man?
Tosh
Because you are using a spare bedroom as your office you can claim a percentage of your gas-electric-water (if on a meter only) and council tax.
You can also claim 100% for office furniture-tea/coffee (if you are making them for you staff or customers or anyone who is connected to your business like visting sales reps etc) you can also claim 100 for decoration and alterations (you need to build an extension and so on).
You CANNOT use this space,other than for business use, so you cannot allow 20% for private use, you also must remove any furniture that this space was originally to be used for (beds-wardrobes-clothing rails etc)
As for using an accountant, well I have been on quite a few courses that the inland revenue hold and I think that I am pretty well clued up on tax rules and regulations, but my accountant has saved me more than his fees this year, he also has reccomended a business grant of £5k that I am also eligible for ( I had never heard of it before).
Also if you make a small error in your accounts returns, this carries on down the time line, so in say 6 years time you undergo a tax investigation, then this small error will come back big time, because all you return figures for the last 6 years are wrong you tax fines and interest could be very costly.
If you don't want a accountant then think about joining the Federation of Small Businesses, because they will help you in any investigation that you might find you under in the future.
Don't forget its not the taxman who calls for an investigation its their computer who ramdonly picks the lucky winners in a lottery of tax payers.