Just found these for £5.49 delivered.
£16+ from Wiggle and Halfords
Ideal for covering the tyres when transporting the bike in the boot of the car
VITTORIA TYRE COVER - 700C PRODUCT DESCRIPTION
The Vittoria Tyre Cover is designed to prolong the life of your tyre. The material used within the product means it is able to block 100% of UV light whilst also being able to stretch to fit all 700c tyres. By also including the hook and loop closures to the product it makes the application and removal of the tyre covers very simple and easy to use, making this an absolute must for anyone trying to maintain their tyres health.
VITTORIA TYRE COVER - 700C FEATURES AND BENEFITS
Designed to protect tyres from the ageing effects of UV light
Will fit all 700c tyres
Hook and loop attachments for easy application and removal
They are also waterproof