I'll try to let you know the extra each is able to provide so you can find the company that caters for your needs.
Direct Line - www.directline.com
Discounts: Up to 10% multi car discount and No Claims bonus.
Offer Courtesy Car and Windscreen Cover
Sainsbury's Car Insurance - www.sainsburysbank.co.uk
Discounts: Second Car discounts and No Claims Bonus.
Offer Courtesy Car and Windscreen Cover
Confused - www.confused.com
Discounts: Online discount, Second Car and No Claims Bonus.
Offer Courtesy Car and Windscreen Cover
Aviva - www.aviva.co.uk
Discounts: 20% Online Discount, Multi Car and No Claims Bonus.
Offer Courtesy Car and Windscreen Cover
Offer Courtesy Car and Windscreen Cover
Admiral - www.admiral.com
Discounts: Up to 10% Online Discount, Multi Car and No Claims Bonus.
Offer Courtesy Car and Windscreen Cover
More Than - www.morethan.com
Discounts: Mirror bonus on second card and No Claims Bonus.
Offer Courtesy Car and Windscreen Cover