You bet - we feed grain free/mostly grain free because ours are mostly indoor and I dont want them eating junk. Although they get junky wet at night but hey, you gotta draw the line somewhere
Zooplus some similar US brands like Taste of the Wild (in the hideous colored bags with mountain lion on the front) which our two like a lot, and that is grain free
http://www.zooplus.co.uk/shop/cats/dry_cat_food/taste_of_the_wildHowever, we have also found Applaws to work very well and is their daily morning brand (oh look! big sale on trial 400g bag for £1!!)
http://www.zooplus.co.uk/shop/cats/dry_cat_food/applaws/640736And they love love LOVE Purizon, but they must have changed formula because it makes Boy Kitty a bit runny now and then he gets confused using the box. Orijen is supposed to be amazing, but its really pricey though. We did try them on Meowing Heads, but it made Girl Kitty barf, so that one got binned as well.
Oh! there is a new brand called Leonardo that is specifically wheat-free cant vouch for it though as we haven't tried it:
http://www.zooplus.co.uk/shop/cats/dry_cat_food/leonardoWhat I love about zooplus is that you can get trial bags for most brands, so no chancing with food that may not get eaten.
For wet, ours like gravy-style but they dont have BFF brand here (their favorite, we brought boxes home from the US for them as a special treat), so we serve Gourmet Perle.
Treats wise - they really like the Cosma dried chicken snax in the tube.
It looks like most shipping is 1-3 days and I suppose we usually do get the order in 3 or 4 days. Just dont expect a slick shipping operation like Amazon, but it WILL get to you, well packed, correct, in time. I just like to give it an extra day or two.