Most PAYG users should be able to save £15 with this deal.
This bundle gives you 1GB data, 500min, 5000 texts per month.
This offer is not very public, here is are the details from support:
The half price Rocket pack is available to new and existing customers. If you are a new Customer you would just need to have top-up for the first time by voucher and text "Discount 10" to 28948 from your phone, wait for the reply with the details of the offer and then text BUY10