Ertai, thanks for the advice. My party consisted of:
Shanna (Bard, lvl 3)
Minsc (Ranger, lvl 1)
Branwen (Cleric, lvl 3)
Dynaheir (Invoker, lvl 1)
Safana (Thief, lvl 2)
Kivan (Ranger, lvl 2)
I managed it after a few reloads by getting one of the group to chase after Minsc, and keeping the rest of the party well out of the way (the other side of the map!).
Then of course I got into the cave, and Minsc was squashed flat in one blow! Got the treasure using stealth & potions of invisibility, but will make a return visit when I am a higher level to wreak my revenge!!! BWAAHAHAHAHA!
All my characters levelled as a result, and I'm really pleased with myself for managing it at a low level!
It wasn't easy, and the one thing I hate about BGI is the way monsters respawn every time you reload - there is no such thing as clearing a map. That makes it a lot harder than BGII IMHO (can you imagine the druid grove with all the trolls respawning every time you reload?).
But it does make the game more of a challenge, and it's an effective way of making sure that reloading isn't overused. Also it makes sure that you can't just level up then reload if you get a low HP roll if you're in the middle of nowhere - you either have to take the HP you're given, or wait until you get back to a safe area to level up. Of course it also means that there are unlimited exp points on offer!
------------------
Time is an illusion. Lunchtime doubly so.
Epona of The Laughing Hyenas.