https://www.worldwideinsure.com/
I just checked. Last time I paid £69.50 for a year's cover. Still pretty good I think.
I have the annual deluxe cover. Covering all of Europe including my country of residence (Estonia)
For future reference. I strongly recommend taking out your own car rental insurance. I hire cars quite often but actually I am in plus normally after only one trip.
I pay £45 per year for the insurance which covers you and any named driver on the policy for unlimited hires up to a maximum of 6...