Mobilis healthcare do a lumbar roll for under £7 which is a good price if you look at the price they cost at some other retailers.
http://www.mobilishealthcare.com/physiotherapy/p-6505-mckenzie-d-roll.aspx
This lumbar support is made of high density foam, making it a firm roll to be used in soft furnishings such as sofas, lounge chairs, etc. The McKenzie D-Shaped Roll is also ideal for people who require lots of support such as those with a large hollow in the lower back or heavy-built people. It relieves and prevents back pain, promoting good posture and the natural ‘S’ shape of the spine.
