Register with Jessops and they will send you a welcome email for signing up which contains a £10 voucher off your first order.
VOUCHER CODE: WELCOMEBOOK
I ordered a Hardback Large Landscape photobook (21cm x 28cm) for only £10.44 including delivery.
It is normally £26.99 (currently on sale at £16.19), plus delivery £4.25, which would normally cost £31.24. With the sale price and the £10 off, its only £10.44.
I believe the £10 voucher can also be used on the other photobooks. There is no mention of a minimum spend. The email says £10 off your first CEWE PHOTOBOOK, but I ordered a normal Jessops one, and the code still worked fine.
Hope this is of use to someone!