Seems a tad too late. Self quarantine will never work in the UK or anywhere else for that matter. They should have adopted what Australia is doing, mandatory quarantine. Had friends coming in from overseas to work in the oil and gas industry and they also where quarantined for 14 days prior to being allowed offshore. Confined to the room for the full 14 days and not allowed outside, food delivers and left outside the room door. Two security people posted on each floor to watch elevators and emergency exits. Not ideal but it did result in Australia having lower cases of Corona victims than most other countries. They are now starting to lift restrictions, slowly but they are being lifted.
Information for returning travellers
Effective from midnight AEDST 28 March 2020, if you’re arriving back in Australia you’ll be subject to the Australian Government’s mandatory quarantine period of 14 days at your first Australian destination.
You’ll be provided with suitable accommodation to stay in during this period. You’ll not be permitted to travel domestically (including to your home) or continue on any domestic connections, until the 14 day mandatory quarantine period has been completed.