Additional £3.49 for non prime customers
Possible additional 20% off for first subscribe and save making it £8.68 delivered,
Save 15% when you schedule repeat deliveries of 5 or more products in one delivery to one address.
Or plus 5% for subscribe and save (£8.14 delivered)
Then cancel subscribe and save after delivery as should be enough to last a few years
(subject to expiry date)