I've started and commented on quite a few Jessops / Digital threads. My posts and opinions are based on my personal experience. If people disagree then that's fine; everyone's entitled to their own opinion.
The darkroom materials and kit have always been on the Jessops site, albeit since the redesign hidden away on submenus. However, the range and quantity stocked even at the warehouse have declined massively over the last few years.
A wide range of traditional materials and accessories used to be on display in most stores so that you could walk in off the street, have a browse, pick it up off the shelf and buy it then and there. When this stopped being common practice it was at least kept in the back room so that you could walk in off the street, ask for it and buy it then and there.
Increasingly I've found it's now a case of, "Well, we can order it for you", or sometimes, "You might be able to go on our website and order it yourself!" (this in the Manchester city centre store a couple of months back for a bottle of fixer!).
If I have to order something and wait for it then I'll go for the lowest online price (which is very rarely Jessops) or (more likely) I'll pick a firm who actively support traditional photography instead of actively discouraging people from buying film cameras and marginalising traditional products at every opportunity.
Online I go to Silverprint, Mr CAD and Nova Darkroom. In the high street I go to Jacobs, who have a great selection of traditional products right out on display. Slightly off the high street but still usually walk-in-and-buy, Calumet are still fairly good for a range of traditional gear. These companies actively support my hobby so I actively support them.
Some of the old-school Jessops staff left over from the good old days are very good indeed. A lot of the new lot know nothing about traditional photography (and, truth be told, not much more about digital!).
Like I said, I'm basing this on my experience. Your Mileage May Vary.