Don't buy 2 or more tyres.
This retail has now refused me twice. They use the get out clause about discounts. But the discount they use is if you by 2 or more tyre ( which is problably what most people buy) you do not get cashback. The only way to get cashback is buy 1 tyre at a time. This is the last time I will be using this retailer, and Quidco should highlight the problem to their members. If you look at the reviews this is a common issue with this retailer.