Charlie
Whilst there are some black and white rules on capital most of it comes under the opinion of a Decision Maker on the day.
The following is the relevant chapter from the Decision Makers Guide
assets.publishing.service.gov.uk/governm...e/774198/dmgch52.pdf Paragraphs 52748 and 52749 cover Notional Capital, as you can see they are of little help.
The limited advice I can give you is not to clear debts that are not due at this time, an example of this would be paying off a mortgage early. Try and keep your expenditure reasonable, building repairs and replacing old or damaged white goods should be OK, a budget car may be acceptable but a luxury holiday might not.
The key issue is whether the expenditure can be seen as being made in order to continue to receive your benefits.
Gordon