If you don't want the hassle of cashback redemptions, then this may be a good deal for 40gb 5G ready data for £17pm. I got this deal over their chat service and it is available through phone too.
18 month SIM only package.
• The plan gives you Unlimited minutes, Unlimited texts and 40 GB of data. The standard monthly cost for this is £20.00 (inc.
VAT),• With your discount you will pay £17.00 each month. This discount runs for 18 Months which will show on your My Vodafone account online.