HMRC provides a couple of ways to pay yourself back for using your home as a business.
Each method can save you different amounts of tax. Its important to get the right method.
HMRC fixed method amounts allows you to claim a fixed amount each month depending on how much time your work from home.
25 - 50 hours per month £10 a month
51 - 100 hours per month £18 a month
101 hours + per month £26 a month
More is better
However, HMRC also allow you to claim for your utilities expenses, council tax rent/mortgage interest based on the proportion used for working. This would involve looking at the room used in relation to the total number of rooms in the house and the number of hours the room is used for.
You should be careful not to use any room wholly for your business as this will effect your primary residence relief when you sell the property. Typically you should try and use the room for other things besides work.
.....and furniture
People focus so much on their working from home reduction that they forget to claim the furniture you use for your business. If this is wholly used for your work, then it can be entirely claimed. If there is a mixture of private and business then this too can be claimed.
Any expenses incurred on fixing these items can also be expenses, although this will be restricted to the private and personal use split.