Looks like the paper's been used... someone made notes on a box. But if they feel fairly full, someone might want them. If some of the chemistry is unopened or hardly used maybe somebody'd want it, but there's probably not much value to it.
If you have a camera swap in your area, that might be the kind of place you could sell it, probably not for much. If this came from someone who had a darkroom chances are it was stored and used properly and at least some of it (the paper anyway) could still be usable. I maybe wouldn't save the mystery jar with the red lid.
edit - Looking again I noticed Jessops so if you're in the UK maybe try looking up
Film's not Dead. | Film Photography Blog & Shop. | ; they used to talk about setting up at the Brick yard? market somewhere...
People doing alternative processes might want some of this. I've used paper way older than this but it has to
not have been exposed to light to be usable. If you want to test it go in a darkened room (not necessarily pitch black just away from a window and sunlight), open the black paper/plastic, take out one sheet, put the rest of the paper back in the black packaging and close it up with the lid on the box. KEEP THE PAPER IN THE DARK. Put the one piece of paper out in the sun or in a window getting lots of sun and the paper should darken. (If you got out a piece of paper and it already looked gray it was probably exposed and to me wouldn't be usable.)
Not sure about the Silk Gutta, can't make out much of the label but that might still be usable for someone doing crafts (it might be for silk painting).
edit again... I'd probably use the fixer; I'd try it on a couple of my lumen prints (the ones that don't turn out that great that I save to run thru some diluted fixer to test it) - the fixer might still be OK. Developer etc. might likely not be worth using.
