Okay in sidebar_leftopen.tmpl - it causes ubbthreads.php to be centred from top to bottom in Opera. Displays fine in IE.
Changing <td align="center" valign="top"> to <td valign="top"> eliminates this problem.
Still trying to track down the other issues, which is affecting 6.3b4
Beginning to wonder if it is my header/footer causing the problems....
..... goes off to investigate them
at the moment - but expanding all the time....) 
