Ok, fair enough, but that's my choice of a luxury.
It's not something you have to spend out on.
Telephone (or proportion of), accountancy fees, advertising, stationery, resin, pre-filters, vehicle maintenance (once your's gets older), clothing. Of course some of these are optional depending if you do your own accounts. Also, maybe you don't need to concern yourself with water as I think Ian supplies that. It may well be that you aren't offsetting all expenditure that you're entitled to. Some of the less obvious items that have appeared in my accounts in recent years include (and I can justify all of them though some are apportioned), sunglasses, washing powder, interest (when I've paid for a business item on a cc), interest on the business proportion of my van loan, a basic tool set to maintain my equipment, heater (for van in Winter), spare keys (for garage lock-up), sealant, battery charger, bicycle pump (for trolley tyres), map (for when I started canvassing a new area) that I wasn't familiar with, rubber matting (to lay over hoses in certain situations), spare blade fuses, FSB membership, weighbridge check (when I wanted to find out how much water I could get in while loaded with other equipment), postage excess (when a customer sent a cheque in an oversized envelope ands only normal postage), several parking fees (not fines), parking permit (proportion) as I live in a resident only parking area, toner cartridges (I print a fair bit of my own stationery), glue, pens, train fare to attend a drought order hearing (not sure if accountant knocked that one off or not), re-imbursuing customer for damage (broke a garden table - oops!! ), spare bulbs for van, anti-virus software (proportion), cordless phone batteries, in car charger for mobile, bed & breakfast (NEC visit for cleaning show), velcro strips, watering can/gardening trowel (I use these to re-fill resin vessels), external hard drive (proportion) to back up accounts files, domain name charges, photocopier usage (don't ask LOL), shredder, and a couple of courses at BWCA.
Although some of those items are small, they are all valid business expenses (or proportions thereof where there is some personal usage). The time it took to enter these on my spreadsheet was less than it took to make this post but it saved me something from my tax bill. The above are not all in one year. I just cast my eye down a column of my spreadsheet to note some of the less obvious ones.
Boring isn't it?