Its very easy to over-complicate your accounts, and the more complicated you make it, the more confused you will be, and ultimately you will have no idea where your accounts are at.
costs are (in the most) tangilbe figures. Even those that are not so exact (such as laundry costs) can be calculated using guidance provided from the Inland Revenue.
We are not accountants and we should leave the complexity of that type of profession to the accountants, otherwise you end up tying yourself in knots and when your tax return is in a mess because you dont have a clue where you are, you will have the Inland Revenue to answer to and will wish you had kept it as simple and straight forward as possible.
Dont try and be an accountant, if you feel you need to keep such intricate accounts, get an accountant. Otherwise, just keep simple, factual and accurate records, and provide records to this effect with your tax return. That way, if there are any discrepancies, you can provide your records to the Inland Revenue who can easily interpret these. You dont need a spreadsheet or even a computer to keep these records, you could buy an accounting book from a stationers. Record the money you take, and the money you spend. You can include your start up costs (eg all those things you have had to buy in order to open you business eg furniture, stock etc). You will be able to use these records to get a running total, and a simpler record like this helps you to see where your business is at a quick glance. If you are unsure about any aspect of record keeping, or what is tax deductable, the inland revenue are extremely helpful with small businesses and also they run some very helpful workshops, some of which are free.
If you really think you need to be keeping intricate and complicated accounts, get an accountant. After all, we are always complaining on this site when untrained people think they can just become techs or therapists, so who are we to assume that we can do the job of an accountant??