The super-cheap rates queeq quotes come with one catch, though: They do not include any kind of insurance. And by any, I mean any - not even legally required liability insurance. See the disclaimer:
No insurance included, such as Third Party Liability Protection, Collision or Theft protection. The option applies to those who have their own insurances. Please obtain a letter of proof that you have insurances which extends to the country of rental at pick-up.
Those rates are not geared at (foreign) tourists.
You will either have to buy insurance from the rental agency at inflated daily rates which will drive up cost significantly or purchase a policy in the UK from specialized vendors like
https://www.icarhireinsurance.com.