Best place to buy online groceries from?

Does anyone have recommendations on shops to order online groceries to have delivered to your home. My wife is a stay at home mom and we used to order a lot of our groceries online and have it home delivered. We would get great organic vegetables and heavy products that were difficult to carry home (liters of water, milk, etc.).

We just moved to London so not that familiar with things. Are prices marked up heavily for delivery foods due to shipping costs here, are they cheaper, can you get better deals by ordering online, how common is it?

Thanks!

I am not familiar with London, but living in both Berkshire and Oxfordshire, I used to order from either ASDA or Tesco.  I believe the prices are the same as in the store (but am open to being corrected).  You pay a delivery fee, which varies depending on the day and time you choose to have your delivery made (my recollection 3-5 quid).  I always thought this was a great deal, as I'd probably burn that in petrol going to the store!  However, I was never satisfied with the quality of fruit or veg include, and I'm not sure how much "organic" stuffs those two stores have.  

You could try Abel & Cole: http://www.abelandcole.co.uk/.  We were close to signing up with them before we discovered a farm down the road that did the same thing.

All the major stores do home delivery, and some have great organic produce. I think it will just be a case of trying and seeing what you think. If the produce isn't up to your standards at least you can have the bulkier grocery items delivered, and shop for fruit and veg in person.

Here's a link to an article rating online shopping in the UK: http://www.dailymail.co.uk/femail/article-1363118/Which-online-supermarket-truly-delivers-Our-secret-shopper-test.html

I think Ocado is pretty good: http://www.ocado.com

We order some things online once every month or two (have an order with 7 big bags of soil coming from ASDA tonight!  Woohoo!) but usually we buy fresh produce, bread and milk in-store.    It's usually heavy stuff (like the soil!) or non-perishables (like jars of pesto and tomato sauce) we order online.

Sometimes we get a voucher for £12 in Nectar points for Sainsbury's (if we do an online shop of £60 or more).  Those are awesome.  

Sometimes there's a minimum order (with ASDA I think it's a £35 minimum) and delivery prices vary by the day and time.  Some supermarkets give free shipping if you spend over a certain amount (£100 for Sainsbury's, I think).  

Waitrose, Sainsbury's, Tesco, etc. - they all have online shopping. As for nicer non-supermarket stuff, there are big veg box delivery services like Riverford and Abel & Cole, or else just have a look at this site: http://www.findlocalproduce.co.uk/Veg_Box_Schemes

You can find a local milkman here: http://www.findmeamilkman.net/

You can do price comparisons on mysupermarket.com of all the big food stores, this may give you an idea of who has what and prices.