search:

http://forums.b2evolution.net/viewtopic.php?t=2958&highlight=file+upload

also

http://forums.b2evolution.net/viewtopic.php?t=3198&highlight=upload+limit

and despite what that last post in the 2nd thread says you CAN set it higher -- if you set it higher than your host allows it will simply use whatever your host has determined it to be in the php.ini

thanks, sorted it now.