EasyClick: For me it was their return policy. On amazon and even John Lewis you could return the package after opening it and using a camera. They would take the product back no questions asked. At Jessops, it wasn't so. If you broke the seal, it was nearly impossible to get a refund unless there was a manufacture problem. That alone lost me as their customer.
Had you made the correct choice with the help of the staff, you wouldn't have had to return an item anyway. The item you subsequently returned would then have to be sold as second-hand or ex-demo, cutting the profit that was made in the first place. You have no legal right to return something if you don't like it. I work in a small camera shop (there are a few of us left) and this sort of customer activity only weakens what little profit we do make, so we do not offer returns unless faulty. Just because all the big companies who can afford to accept an unwanted item back doesn't mean customers should expect it everywhere. With this attitude, no wonder the high street is getting more barren on a daily basis!