Capital Allowances

[bobcat7]

I'm not 100% sure about what counts as Capital Allowances & how it's calculated. Please excuse me if I'm asking the obvious – but do I understand this right?
(I'm not concerned about limits for AIA, my overall expenses are well below £10k anyway)

Any kind of computer hardware and software = Capital Allowance
Claimable as Annual Investment Allowance, at a 100% relief.
So if my laptop cost £800, I claim £800. If I sell it a year later for £500, I count £500 as an income.

Inks for my printer = normal expense

How about spare parts? Let's say my laptop screen breaks. I get it replaced for £200.
Is that a normal expense (such as inkjet inks), or should I count it towards Capital Allowance?

Sorry for such a daft question. My annual turnover is below £20000. And I'm looking forward to next year when I can hopefully justify/afford an accountant to do this for me.

[section 44]

repair/replacement expenditure is typcially revenue in nature (i.e. capital allowances not in point) and (subject to usual rules) deductible against income.