The quarantine website provides information about rabies quarantine in the United Kingdom for cats, dogs and other rabies susceptible animals that do not qualify for entry into the UK under the Pet Travel Scheme and are required by law to spend 6 months in quarantine.

Procedures - Guidance on choosing a quarantine premises.
Approved premises - List of UK authorised quarantine premises and carrying agents
Welfare of animals in quarantine
This comes from this site. It has all you need to know about pets entering or travelling to the EU or from 1 EU state to another.