Oh FGS! Read the article.
They used £30k to refurbish the Flat that is allowed for all prime Ministers and put some of ther own money in as well. No public money was spent on their furniture etc.
"The other £653,192.34 was spent on external and internal renovation work to the offices and reception rooms in Downing Street, including cabling, plumbing and energy efficiency improvements."
This is a public building and vast majority of the money was spent on public rooms in a Grade I Listed building. What do you expect? Pop down B&Q and get a few tins of magnolia and do it all themselves?