jono32 wrote:Can't work out why this would suddenly happen.
Because things generally don't last forever, just because something was previously never broken, doesn't mean it won't ever break.
What kind of leak is it? Vapour thats quickly condensing on the outside of the column or is liquid exiting? Have you tried using PTFE tape or flour paste to seal the bottom and see if you're getting pressure build up or leaks elsewhere?
Also, posting two of the same post might just muddy the replies.