Any good of UK conditions i.e. does it suffer from condensation and what about weathering up in a storm?

Seam sealing a Jetpacker.I see Branwen Welsh got a leaky one. Why not try the manufacturers recommendation? Banana Oil.
It ain't made from Bananas, just smells like it. It's primarily used to taste fish bait, but if you cut it with thinners (I use 50:50)you can paint it along the seams and it dries to a good flexible impermeable colourless finish.Obtainable from angling shops,it's
expensive ( £9 a small bottle )but goes a long way.I sold half the bottle back to the Store manager!

they are amall and very reliable. i have one that might be 15 yrs old now, it has a cotton type inner, and its always been nothing less than brilliant. really were the bees knees, at less than 1.5kgs. a bit pushed for space in the vestibule! most people used to put their pac in a bin liner and sit it outside, that way you could keep your boots out of the rain. for me they were a solid 10/10.