Managed to get this deal.
Salesperson discounted handset from £34.95 to £29.95. National offer of £20 credit for £10. Accessory sock free. All l needed to be was an existing vodafone PAYG customer (l am) and he put it through till as upgrade. Credit could be added to anyones Vodafone PAYG mobile. Mobile then comes out at £19.95 if free £10 credit is discounted.