I do all my shopping via Ocado!
My top tip?
Choose you recipes from BBC Good Food or Jamie Oliver's website and click 'add to basket', add the ingredients you don't have in the cupboard and wonderful meals and superfast shopping are yours for the taking.
I cannot recommend Ocado enough. Our first ever delivery, seven weeks before our son was due, well I had some stomach pains, left a note on the door and went to hospital for a check up... gave birth to him that evening and MiL came over to our shopping carefully put in the garden, OH was grateful as he had food! I emailed Ocado to say 'thank you' and they sent me a bottle of wine. All the drivers are polite and well mannered. I've had two substitutions in 16 months and even better I can give my shopping backs back to the driver for a 5p refund off my shopping, they accept bags from other shops too.
Plus the APP, it was a LIFESAVER when we had a tiny newborn, I could finish the shop off whist feeding at 2am and you can scan barcodes of things you run out of to add them to your basket. Fruit and veg has always been of a very high quality too.
As for other supermarkets, we used to use Tesco and they were forever substituting things, poor quality vegetables or weird glitches in the system (did I really order 11 pots of sour cream by accident) not to mention the slightly surly drivers...
I just can't recommend Ocado enough!