Hi Nick,
I would say that the replacement of the carpet is an asset (Fixtures and Equipment) as it has a fairly long life expectancy and is also a significant cost to the business. It depends a bit on how much you paid.
You can post it to office furniture or create a new one.
I am sure that others may argue that it could be a repair or renewal as it was a replacement for what was previoulsy there.
The paint I would post to maintenance and your little finishes to repair or maintenance as well.
If those nominal accounts are not in your quickfile account you can easily create these accounts:
I am not an accountant and you should always ask one. Your accountant knows your books and there could be little things which influence the choice of the right nominal account.