Hi all, sorry for the delay.
Yes the 3450i comes with the appropriate tip, and the charger is a universal power supply like for a laptop - should work anywhere with the right plug lead.
Agreed 3450i is the one to get - you just set the voltage with some dip switches and never think about it again (other than plugging it in when it gets low).
I had problems with the charger power supplies for some reason - two died. Bought a different laptop charger on ebay and it works fine, seems more robust - even charging two batteries at once with a splitter. You can charge it with a range of voltages, but 6V from the Elektron power supply is too low.
Just to be clear I had my problems only with the power supply that comes with the battery to charge it - the batteries themselves have all been very solid.
Prices seem to have varied - I know I paid more than the bh photo price I posted before.
Haven't timed it running flat on the OT actually, but I'd guess 4-5 hours...? If anyone else has experimented I'd be interested to hear.
It even gives nice loud beeps when it's really low to let you know to save your project before it goes flat. Saved me a couple of times when I lost track of time
Finally, one single battery will fit in the front packet of the Elektron Carry Case with your favourite ear buds. Convenient freedom!