Only just realised this when I was setting up a new offer

I was attempting to create a coupon that discounts the value of a particular item when the order total is over £50.

So I set min order £50
Then product restriction with the product that would be discounted

I now realise zen can't do this. It was expecting. £50 worth of the restricted product not the order total.

What I want to try and achieve is:

Coupon valid when:

Restricted product is present in cart
And
Overall shopping cart value is above £50

Can any of the gurus advise how I can modify the code to make it work in this way please?

Thanks