The Red Bike Shop

Really helpful and friendly staff the two times I was there. Discovered this place by accident when I got a puncture near there. They fixed it more quickly and cheaply than my local overpriced Stoke Newington bike shop. They also seem to have a decent selection of cycling accessories and some new and second hand bikes for sale.
Took bike for a «light service» a few weeks later. They have different levels that are accurately described and have a clear pricing structure. I really liked this, since I knew that I just wanted simple things like brake and gear tightening. The light service was £30 which seemed reasonable for Islington. They were honest about things that needed to be replaced (new brake pads, which I knew anyway) but I liked that they didn’t attempt to up sell me a more expensive service like other shops have.

As a new business in Islington these guys deserve your trade. I stopped in with my bike that I recently bought second hand from a friend. Without going into too much detail it needs a bit of work but still does the job. The Red Bike Shop guys helped immensely to rig something up so I could get back on the road with minimum fuss and cost.
Local bike shops are important in London and this isn’t the type of place that only sells expensive off the peg bikes. They are more than willing to get their hands dirty. If you are looking for a complete new bike they do also stock bikes that are already made up that seemed reasonably priced. The key thing is the staff seem knowledgeable and passionate about cycling. They stock all the extras keen cyclists like to browse through and they were willing to order things in as well.
In short try the Red Bike Shop if you’re into cycling or are looking for a new bike.