I made a batch last week. I've used my mother-in-law's perfectly good recipe before, but this time I used a recipe I found in the Times' style section because it looked like it might be more like Cooper's Oxford (it had a hint of treacle in it). And it's quite delicious, if I say so myself! Homemade marmalade is a lot more work than your standard jam, but you won't be disappointed. The flavour is out of this world.
The point where I failed was sealing the jars. I bought those waxed paper disks, and the woman at the shop told me you just lay one on top of the hot marmalade in its jar and it will seal. Well, it didn't work like that. The paper slipped under the jam, crumpled, did everything but sit neatly and seal. Now I've got jars in the freezer, jars in the fridge...and storage is a real challenge in both.
I'd be happy to send you my recipe if you like. The ingredients are slightly different from, say, Delia's, but the procedure is the same.