Is a laptop battery an asset (under office equipment) or a consumable (because in 2 or 3 years it will be dead)?
I assume headphone are “office equipment”. (And they are - they are noise cancelling headphones bought specifically to deal with a noisy office I am contracting in).
It is something that different accountants will probably have different views on specifically. I follow the rule above and have seen it mentioned before, but there is nothing wrong with categorising every payment specifically. The only thing to be aware of is assets will generally need to be depreciated and stock is treated differently to general purchases on balance sheets so it can sometimes be more hassle than it’s worth to itemise every small purchase for the office as an asset, hence the rule of ‘<£3-500 = general purchase’. Each to their own though.
As for asking accountancy questions, ask away. There are a few accountants and bookkeepers around and a few users with some experience and knowledge in these matters.
That advice explicitly says that the formation fee goes under assets because it isn’t an expense that can be claimed against Corporation Tax.
The degree of granuality in classifying deductible expenses is really down to you. Personally I would have put the batteries down to consumables and the phones as general expenses.
If you ask a group of accountants the same questions, it’s very likely you’ll get different answers. Just head over to AccountingWeb for evidence of this.
In fact here’s a discussion on AccountingWeb related to your question about Company Formation fees. See the differing opinions.