I've used Jessops for years and I've always found them to be helpful in the extreme. It seems that they're quite happy to take the time to allow you to inspect goods, look at alternatives etc etc.
And they don't even seem to demand that you buy that day. If you say you need to take a few days to make up your mind, then that's OK.
In my early days, I even used the day training faciities and courses at their Leicester store. They do seem committed to making your photo experience a good one.