If Amazon Fresh is available in your area you can be eligible for a 30 day trial if you have Prime, or you can sign up to the 30 day Prime trial and Amazon Fresh at the same time. If you spend over £60 you can get a FREE £20 Amazon Credit. Delivery is free over £40 so it seems like a good deal if you can get it (33% back in Amazon Credit).
I believe it is available in London and I'm sure it will be rolled out to more places like PrimeNOW has. So this is also a heads up for those outside the eligible area.
Offer is limited to one per customer and account.
To qualify to receive your £20 Amazon.co.uk gift card:
Sign up for your FREE 30-day trial of AmazonFresh. If you are not currently a Prime member, you will also need to sign up for Prime (or a 30-day free trial of Prime if eligible).
Reserve your one-hour slot for delivery between 16 - 30 June, 2016.
Place an order of AmazonFresh products (“Qualifying Items”) of £60 or more (“Minimum Purchase”) for delivery between 16 - 30 June, 2016.
Within 72 hours of your delivery, we’ll automatically apply a £20 Amazon.co.uk gift card (“The Offer”) to your account and send you a confirmation email.
Enjoy shopping with your £20 Amazon.co.uk gift card!
Also I found that Daylesford Organic Farm produce has a 20% off promotion, theoretically you can get £75 worth of Daylesford Organic food for £40 (after 20% off to £60 and then £20 Amazon credit). There may be more offers on other brands of produce. https://www.amazon.co.uk//l/ref=s9_acss_bw_cg_ukdfmt1_2c1?node=8580503031&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=merchandised-fresh-search-5&pf_rd_r=VFDE0PC1RJC7Q0YCVKTH&pf_rd_t=101&pf_rd_p=973184327&pf_rd_i=8662693031