Sending a value of BTC0.00
How would someone send £0.00?


The transaction you mentioned sent .00001 BTC to
19BY2XCgbDe6WtTVbTyzM9eR3LYr6VitWK which is the Shadow Brokers account. £0.00 is only a rounded number when converting to fiat. Disregarding this transaction, it is possible to send Bitcoin transactions with no BTC value


  why would someone send £0.00?


Your why question is more speculative, but sending dust is a common (low cost) tactic for chain analysis companies to tie bitcoin addresses together in the future. In this case it is likely that many chain analysis companies (on their own or on behalf of government clients) will attempt to identify the owners of that Bitcoin account.